X-Git-Url: https://oss.titaniummirror.com/gitweb/?a=blobdiff_plain;f=gcc%2Ftree-ssa-sccvn.c;fp=gcc%2Ftree-ssa-sccvn.c;h=539abf6a3f486f62f5411bff831afb8c5da76aff;hb=6fed43773c9b0ce596dca5686f37ac3fc0fa11c0;hp=0000000000000000000000000000000000000000;hpb=27b11d56b743098deb193d510b337ba22dc52e5c;p=msp430-gcc.git diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c new file mode 100644 index 00000000..539abf6a --- /dev/null +++ b/gcc/tree-ssa-sccvn.c @@ -0,0 +1,3145 @@ +/* SCC value numbering for trees + Copyright (C) 2006, 2007, 2008, 2009 + Free Software Foundation, Inc. + Contributed by Daniel Berlin + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 3, or (at your option) +any later version. + +GCC is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING3. If not see +. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "ggc.h" +#include "tree.h" +#include "basic-block.h" +#include "diagnostic.h" +#include "tree-inline.h" +#include "tree-flow.h" +#include "gimple.h" +#include "tree-dump.h" +#include "timevar.h" +#include "fibheap.h" +#include "hashtab.h" +#include "tree-iterator.h" +#include "real.h" +#include "alloc-pool.h" +#include "tree-pass.h" +#include "flags.h" +#include "bitmap.h" +#include "langhooks.h" +#include "cfgloop.h" +#include "params.h" +#include "tree-ssa-propagate.h" +#include "tree-ssa-sccvn.h" + +/* This algorithm is based on the SCC algorithm presented by Keith + Cooper and L. Taylor Simpson in "SCC-Based Value numbering" + (http://citeseer.ist.psu.edu/41805.html). In + straight line code, it is equivalent to a regular hash based value + numbering that is performed in reverse postorder. + + For code with cycles, there are two alternatives, both of which + require keeping the hashtables separate from the actual list of + value numbers for SSA names. + + 1. Iterate value numbering in an RPO walk of the blocks, removing + all the entries from the hashtable after each iteration (but + keeping the SSA name->value number mapping between iterations). + Iterate until it does not change. + + 2. Perform value numbering as part of an SCC walk on the SSA graph, + iterating only the cycles in the SSA graph until they do not change + (using a separate, optimistic hashtable for value numbering the SCC + operands). + + The second is not just faster in practice (because most SSA graph + cycles do not involve all the variables in the graph), it also has + some nice properties. + + One of these nice properties is that when we pop an SCC off the + stack, we are guaranteed to have processed all the operands coming from + *outside of that SCC*, so we do not need to do anything special to + ensure they have value numbers. + + Another nice property is that the SCC walk is done as part of a DFS + of the SSA graph, which makes it easy to perform combining and + simplifying operations at the same time. + + The code below is deliberately written in a way that makes it easy + to separate the SCC walk from the other work it does. + + In order to propagate constants through the code, we track which + expressions contain constants, and use those while folding. In + theory, we could also track expressions whose value numbers are + replaced, in case we end up folding based on expression + identities. + + In order to value number memory, we assign value numbers to vuses. + This enables us to note that, for example, stores to the same + address of the same value from the same starting memory states are + equivalent. + TODO: + + 1. We can iterate only the changing portions of the SCC's, but + I have not seen an SCC big enough for this to be a win. + 2. If you differentiate between phi nodes for loops and phi nodes + for if-then-else, you can properly consider phi nodes in different + blocks for equivalence. + 3. We could value number vuses in more cases, particularly, whole + structure copies. +*/ + +/* The set of hashtables and alloc_pool's for their items. */ + +typedef struct vn_tables_s +{ + htab_t nary; + htab_t phis; + htab_t references; + struct obstack nary_obstack; + alloc_pool phis_pool; + alloc_pool references_pool; +} *vn_tables_t; + +static htab_t constant_to_value_id; +static bitmap constant_value_ids; + + +/* Valid hashtables storing information we have proven to be + correct. */ + +static vn_tables_t valid_info; + +/* Optimistic hashtables storing information we are making assumptions about + during iterations. */ + +static vn_tables_t optimistic_info; + +/* Pointer to the set of hashtables that is currently being used. + Should always point to either the optimistic_info, or the + valid_info. */ + +static vn_tables_t current_info; + + +/* Reverse post order index for each basic block. */ + +static int *rpo_numbers; + +#define SSA_VAL(x) (VN_INFO ((x))->valnum) + +/* This represents the top of the VN lattice, which is the universal + value. */ + +tree VN_TOP; + +/* Unique counter for our value ids. */ + +static unsigned int next_value_id; + +/* Next DFS number and the stack for strongly connected component + detection. */ + +static unsigned int next_dfs_num; +static VEC (tree, heap) *sccstack; + +static bool may_insert; + + +DEF_VEC_P(vn_ssa_aux_t); +DEF_VEC_ALLOC_P(vn_ssa_aux_t, heap); + +/* Table of vn_ssa_aux_t's, one per ssa_name. The vn_ssa_aux_t objects + are allocated on an obstack for locality reasons, and to free them + without looping over the VEC. */ + +static VEC (vn_ssa_aux_t, heap) *vn_ssa_aux_table; +static struct obstack vn_ssa_aux_obstack; + +/* Return the value numbering information for a given SSA name. */ + +vn_ssa_aux_t +VN_INFO (tree name) +{ + vn_ssa_aux_t res = VEC_index (vn_ssa_aux_t, vn_ssa_aux_table, + SSA_NAME_VERSION (name)); + gcc_assert (res); + return res; +} + +/* Set the value numbering info for a given SSA name to a given + value. */ + +static inline void +VN_INFO_SET (tree name, vn_ssa_aux_t value) +{ + VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table, + SSA_NAME_VERSION (name), value); +} + +/* Initialize the value numbering info for a given SSA name. + This should be called just once for every SSA name. */ + +vn_ssa_aux_t +VN_INFO_GET (tree name) +{ + vn_ssa_aux_t newinfo; + + newinfo = XOBNEW (&vn_ssa_aux_obstack, struct vn_ssa_aux); + memset (newinfo, 0, sizeof (struct vn_ssa_aux)); + if (SSA_NAME_VERSION (name) >= VEC_length (vn_ssa_aux_t, vn_ssa_aux_table)) + VEC_safe_grow (vn_ssa_aux_t, heap, vn_ssa_aux_table, + SSA_NAME_VERSION (name) + 1); + VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table, + SSA_NAME_VERSION (name), newinfo); + return newinfo; +} + + +/* Get the representative expression for the SSA_NAME NAME. Returns + the representative SSA_NAME if there is no expression associated with it. */ + +tree +vn_get_expr_for (tree name) +{ + vn_ssa_aux_t vn = VN_INFO (name); + gimple def_stmt; + tree expr = NULL_TREE; + + if (vn->valnum == VN_TOP) + return name; + + /* If the value-number is a constant it is the representative + expression. */ + if (TREE_CODE (vn->valnum) != SSA_NAME) + return vn->valnum; + + /* Get to the information of the value of this SSA_NAME. */ + vn = VN_INFO (vn->valnum); + + /* If the value-number is a constant it is the representative + expression. */ + if (TREE_CODE (vn->valnum) != SSA_NAME) + return vn->valnum; + + /* Else if we have an expression, return it. */ + if (vn->expr != NULL_TREE) + return vn->expr; + + /* Otherwise use the defining statement to build the expression. */ + def_stmt = SSA_NAME_DEF_STMT (vn->valnum); + + /* If the value number is a default-definition or a PHI result + use it directly. */ + if (gimple_nop_p (def_stmt) + || gimple_code (def_stmt) == GIMPLE_PHI) + return vn->valnum; + + if (!is_gimple_assign (def_stmt)) + return vn->valnum; + + /* FIXME tuples. This is incomplete and likely will miss some + simplifications. */ + switch (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt))) + { + case tcc_reference: + if ((gimple_assign_rhs_code (def_stmt) == VIEW_CONVERT_EXPR + || gimple_assign_rhs_code (def_stmt) == REALPART_EXPR + || gimple_assign_rhs_code (def_stmt) == IMAGPART_EXPR) + && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME) + expr = fold_build1 (gimple_assign_rhs_code (def_stmt), + gimple_expr_type (def_stmt), + TREE_OPERAND (gimple_assign_rhs1 (def_stmt), 0)); + break; + + case tcc_unary: + expr = fold_build1 (gimple_assign_rhs_code (def_stmt), + gimple_expr_type (def_stmt), + gimple_assign_rhs1 (def_stmt)); + break; + + case tcc_binary: + expr = fold_build2 (gimple_assign_rhs_code (def_stmt), + gimple_expr_type (def_stmt), + gimple_assign_rhs1 (def_stmt), + gimple_assign_rhs2 (def_stmt)); + break; + + default:; + } + if (expr == NULL_TREE) + return vn->valnum; + + /* Cache the expression. */ + vn->expr = expr; + + return expr; +} + + +/* Free a phi operation structure VP. */ + +static void +free_phi (void *vp) +{ + vn_phi_t phi = (vn_phi_t) vp; + VEC_free (tree, heap, phi->phiargs); +} + +/* Free a reference operation structure VP. */ + +static void +free_reference (void *vp) +{ + vn_reference_t vr = (vn_reference_t) vp; + VEC_free (vn_reference_op_s, heap, vr->operands); +} + +/* Hash table equality function for vn_constant_t. */ + +static int +vn_constant_eq (const void *p1, const void *p2) +{ + const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1; + const struct vn_constant_s *vc2 = (const struct vn_constant_s *) p2; + + if (vc1->hashcode != vc2->hashcode) + return false; + + return vn_constant_eq_with_type (vc1->constant, vc2->constant); +} + +/* Hash table hash function for vn_constant_t. */ + +static hashval_t +vn_constant_hash (const void *p1) +{ + const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1; + return vc1->hashcode; +} + +/* Lookup a value id for CONSTANT and return it. If it does not + exist returns 0. */ + +unsigned int +get_constant_value_id (tree constant) +{ + void **slot; + struct vn_constant_s vc; + + vc.hashcode = vn_hash_constant_with_type (constant); + vc.constant = constant; + slot = htab_find_slot_with_hash (constant_to_value_id, &vc, + vc.hashcode, NO_INSERT); + if (slot) + return ((vn_constant_t)*slot)->value_id; + return 0; +} + +/* Lookup a value id for CONSTANT, and if it does not exist, create a + new one and return it. If it does exist, return it. */ + +unsigned int +get_or_alloc_constant_value_id (tree constant) +{ + void **slot; + vn_constant_t vc = XNEW (struct vn_constant_s); + + vc->hashcode = vn_hash_constant_with_type (constant); + vc->constant = constant; + slot = htab_find_slot_with_hash (constant_to_value_id, vc, + vc->hashcode, INSERT); + if (*slot) + { + free (vc); + return ((vn_constant_t)*slot)->value_id; + } + vc->value_id = get_next_value_id (); + *slot = vc; + bitmap_set_bit (constant_value_ids, vc->value_id); + return vc->value_id; +} + +/* Return true if V is a value id for a constant. */ + +bool +value_id_constant_p (unsigned int v) +{ + return bitmap_bit_p (constant_value_ids, v); +} + +/* Compare two reference operands P1 and P2 for equality. Return true if + they are equal, and false otherwise. */ + +static int +vn_reference_op_eq (const void *p1, const void *p2) +{ + const_vn_reference_op_t const vro1 = (const_vn_reference_op_t) p1; + const_vn_reference_op_t const vro2 = (const_vn_reference_op_t) p2; + + return vro1->opcode == vro2->opcode + && types_compatible_p (vro1->type, vro2->type) + && expressions_equal_p (vro1->op0, vro2->op0) + && expressions_equal_p (vro1->op1, vro2->op1) + && expressions_equal_p (vro1->op2, vro2->op2); +} + +/* Compute the hash for a reference operand VRO1. */ + +static hashval_t +vn_reference_op_compute_hash (const vn_reference_op_t vro1) +{ + hashval_t result = 0; + if (vro1->op0) + result += iterative_hash_expr (vro1->op0, vro1->opcode); + if (vro1->op1) + result += iterative_hash_expr (vro1->op1, vro1->opcode); + if (vro1->op2) + result += iterative_hash_expr (vro1->op2, vro1->opcode); + return result; +} + +/* Return the hashcode for a given reference operation P1. */ + +static hashval_t +vn_reference_hash (const void *p1) +{ + const_vn_reference_t const vr1 = (const_vn_reference_t) p1; + return vr1->hashcode; +} + +/* Compute a hash for the reference operation VR1 and return it. */ + +hashval_t +vn_reference_compute_hash (const vn_reference_t vr1) +{ + hashval_t result = 0; + tree v; + int i; + vn_reference_op_t vro; + + for (i = 0; VEC_iterate (tree, vr1->vuses, i, v); i++) + result += iterative_hash_expr (v, 0); + for (i = 0; VEC_iterate (vn_reference_op_s, vr1->operands, i, vro); i++) + result += vn_reference_op_compute_hash (vro); + + return result; +} + +/* Return true if reference operations P1 and P2 are equivalent. This + means they have the same set of operands and vuses. */ + +int +vn_reference_eq (const void *p1, const void *p2) +{ + tree v; + int i; + vn_reference_op_t vro; + + const_vn_reference_t const vr1 = (const_vn_reference_t) p1; + const_vn_reference_t const vr2 = (const_vn_reference_t) p2; + if (vr1->hashcode != vr2->hashcode) + return false; + + if (vr1->vuses == vr2->vuses + && vr1->operands == vr2->operands) + return true; + + /* Impossible for them to be equivalent if they have different + number of vuses. */ + if (VEC_length (tree, vr1->vuses) != VEC_length (tree, vr2->vuses)) + return false; + + /* We require that address operands be canonicalized in a way that + two memory references will have the same operands if they are + equivalent. */ + if (VEC_length (vn_reference_op_s, vr1->operands) + != VEC_length (vn_reference_op_s, vr2->operands)) + return false; + + /* The memory state is more often different than the address of the + store/load, so check it first. */ + for (i = 0; VEC_iterate (tree, vr1->vuses, i, v); i++) + { + if (VEC_index (tree, vr2->vuses, i) != v) + return false; + } + + for (i = 0; VEC_iterate (vn_reference_op_s, vr1->operands, i, vro); i++) + { + if (!vn_reference_op_eq (VEC_index (vn_reference_op_s, vr2->operands, i), + vro)) + return false; + } + return true; +} + +/* Place the vuses from STMT into *result. */ + +static inline void +vuses_to_vec (gimple stmt, VEC (tree, gc) **result) +{ + ssa_op_iter iter; + tree vuse; + + if (!stmt) + return; + + VEC_reserve_exact (tree, gc, *result, + num_ssa_operands (stmt, SSA_OP_VIRTUAL_USES)); + + FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VIRTUAL_USES) + VEC_quick_push (tree, *result, vuse); +} + + +/* Copy the VUSE names in STMT into a vector, and return + the vector. */ + +static VEC (tree, gc) * +copy_vuses_from_stmt (gimple stmt) +{ + VEC (tree, gc) *vuses = NULL; + + vuses_to_vec (stmt, &vuses); + + return vuses; +} + +/* Place the vdefs from STMT into *result. */ + +static inline void +vdefs_to_vec (gimple stmt, VEC (tree, gc) **result) +{ + ssa_op_iter iter; + tree vdef; + + if (!stmt) + return; + + *result = VEC_alloc (tree, gc, num_ssa_operands (stmt, SSA_OP_VIRTUAL_DEFS)); + + FOR_EACH_SSA_TREE_OPERAND (vdef, stmt, iter, SSA_OP_VIRTUAL_DEFS) + VEC_quick_push (tree, *result, vdef); +} + +/* Copy the names of vdef results in STMT into a vector, and return + the vector. */ + +static VEC (tree, gc) * +copy_vdefs_from_stmt (gimple stmt) +{ + VEC (tree, gc) *vdefs = NULL; + + vdefs_to_vec (stmt, &vdefs); + + return vdefs; +} + +/* Place for shared_v{uses/defs}_from_stmt to shove vuses/vdefs. */ +static VEC (tree, gc) *shared_lookup_vops; + +/* Copy the virtual uses from STMT into SHARED_LOOKUP_VOPS. + This function will overwrite the current SHARED_LOOKUP_VOPS + variable. */ + +VEC (tree, gc) * +shared_vuses_from_stmt (gimple stmt) +{ + VEC_truncate (tree, shared_lookup_vops, 0); + vuses_to_vec (stmt, &shared_lookup_vops); + + return shared_lookup_vops; +} + +/* Copy the operations present in load/store REF into RESULT, a vector of + vn_reference_op_s's. */ + +void +copy_reference_ops_from_ref (tree ref, VEC(vn_reference_op_s, heap) **result) +{ + if (TREE_CODE (ref) == TARGET_MEM_REF) + { + vn_reference_op_s temp; + + memset (&temp, 0, sizeof (temp)); + /* We do not care for spurious type qualifications. */ + temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref)); + temp.opcode = TREE_CODE (ref); + temp.op0 = TMR_SYMBOL (ref) ? TMR_SYMBOL (ref) : TMR_BASE (ref); + temp.op1 = TMR_INDEX (ref); + VEC_safe_push (vn_reference_op_s, heap, *result, &temp); + + memset (&temp, 0, sizeof (temp)); + temp.type = NULL_TREE; + temp.opcode = TREE_CODE (ref); + temp.op0 = TMR_STEP (ref); + temp.op1 = TMR_OFFSET (ref); + VEC_safe_push (vn_reference_op_s, heap, *result, &temp); + return; + } + + /* For non-calls, store the information that makes up the address. */ + + while (ref) + { + vn_reference_op_s temp; + + memset (&temp, 0, sizeof (temp)); + /* We do not care for spurious type qualifications. */ + temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref)); + temp.opcode = TREE_CODE (ref); + + switch (temp.opcode) + { + case ALIGN_INDIRECT_REF: + case INDIRECT_REF: + /* The only operand is the address, which gets its own + vn_reference_op_s structure. */ + break; + case MISALIGNED_INDIRECT_REF: + temp.op0 = TREE_OPERAND (ref, 1); + break; + case BIT_FIELD_REF: + /* Record bits and position. */ + temp.op0 = TREE_OPERAND (ref, 1); + temp.op1 = TREE_OPERAND (ref, 2); + break; + case COMPONENT_REF: + /* The field decl is enough to unambiguously specify the field, + a matching type is not necessary and a mismatching type + is always a spurious difference. */ + temp.type = NULL_TREE; + /* If this is a reference to a union member, record the union + member size as operand. Do so only if we are doing + expression insertion (during FRE), as PRE currently gets + confused with this. */ + if (may_insert + && TREE_OPERAND (ref, 2) == NULL_TREE + && TREE_CODE (DECL_CONTEXT (TREE_OPERAND (ref, 1))) == UNION_TYPE + && integer_zerop (DECL_FIELD_OFFSET (TREE_OPERAND (ref, 1))) + && integer_zerop (DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1)))) + temp.op0 = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (ref, 1))); + else + { + /* Record field as operand. */ + temp.op0 = TREE_OPERAND (ref, 1); + temp.op1 = TREE_OPERAND (ref, 2); + } + break; + case ARRAY_RANGE_REF: + case ARRAY_REF: + /* Record index as operand. */ + temp.op0 = TREE_OPERAND (ref, 1); + temp.op1 = TREE_OPERAND (ref, 2); + temp.op2 = TREE_OPERAND (ref, 3); + break; + case STRING_CST: + case INTEGER_CST: + case COMPLEX_CST: + case VECTOR_CST: + case REAL_CST: + case CONSTRUCTOR: + case VAR_DECL: + case PARM_DECL: + case CONST_DECL: + case RESULT_DECL: + case SSA_NAME: + temp.op0 = ref; + break; + case ADDR_EXPR: + if (is_gimple_min_invariant (ref)) + { + temp.op0 = ref; + break; + } + /* Fallthrough. */ + /* These are only interesting for their operands, their + existence, and their type. They will never be the last + ref in the chain of references (IE they require an + operand), so we don't have to put anything + for op* as it will be handled by the iteration */ + case IMAGPART_EXPR: + case REALPART_EXPR: + case VIEW_CONVERT_EXPR: + break; + default: + gcc_unreachable (); + } + VEC_safe_push (vn_reference_op_s, heap, *result, &temp); + + if (REFERENCE_CLASS_P (ref) + || (TREE_CODE (ref) == ADDR_EXPR + && !is_gimple_min_invariant (ref))) + ref = TREE_OPERAND (ref, 0); + else + ref = NULL_TREE; + } +} + +/* Re-create a reference tree from the reference ops OPS. + Returns NULL_TREE if the ops were not handled. + This routine needs to be kept in sync with copy_reference_ops_from_ref. */ + +static tree +get_ref_from_reference_ops (VEC(vn_reference_op_s, heap) *ops) +{ + vn_reference_op_t op; + unsigned i; + tree ref, *op0_p = &ref; + + for (i = 0; VEC_iterate (vn_reference_op_s, ops, i, op); ++i) + { + switch (op->opcode) + { + case CALL_EXPR: + return NULL_TREE; + + case ALIGN_INDIRECT_REF: + case INDIRECT_REF: + *op0_p = build1 (op->opcode, op->type, NULL_TREE); + op0_p = &TREE_OPERAND (*op0_p, 0); + break; + + case MISALIGNED_INDIRECT_REF: + *op0_p = build2 (MISALIGNED_INDIRECT_REF, op->type, + NULL_TREE, op->op0); + op0_p = &TREE_OPERAND (*op0_p, 0); + break; + + case BIT_FIELD_REF: + *op0_p = build3 (BIT_FIELD_REF, op->type, NULL_TREE, + op->op0, op->op1); + op0_p = &TREE_OPERAND (*op0_p, 0); + break; + + case COMPONENT_REF: + *op0_p = build3 (COMPONENT_REF, TREE_TYPE (op->op0), NULL_TREE, + op->op0, op->op1); + op0_p = &TREE_OPERAND (*op0_p, 0); + break; + + case ARRAY_RANGE_REF: + case ARRAY_REF: + *op0_p = build4 (op->opcode, op->type, NULL_TREE, + op->op0, op->op1, op->op2); + op0_p = &TREE_OPERAND (*op0_p, 0); + break; + + case STRING_CST: + case INTEGER_CST: + case COMPLEX_CST: + case VECTOR_CST: + case REAL_CST: + case CONSTRUCTOR: + case VAR_DECL: + case PARM_DECL: + case CONST_DECL: + case RESULT_DECL: + case SSA_NAME: + *op0_p = op->op0; + break; + + case ADDR_EXPR: + if (op->op0 != NULL_TREE) + { + gcc_assert (is_gimple_min_invariant (op->op0)); + *op0_p = op->op0; + break; + } + /* Fallthrough. */ + case IMAGPART_EXPR: + case REALPART_EXPR: + case VIEW_CONVERT_EXPR: + *op0_p = build1 (op->opcode, op->type, NULL_TREE); + op0_p = &TREE_OPERAND (*op0_p, 0); + break; + + default: + return NULL_TREE; + } + } + + return ref; +} + +/* Copy the operations present in load/store/call REF into RESULT, a vector of + vn_reference_op_s's. */ + +void +copy_reference_ops_from_call (gimple call, + VEC(vn_reference_op_s, heap) **result) +{ + vn_reference_op_s temp; + unsigned i; + + /* Copy the type, opcode, function being called and static chain. */ + memset (&temp, 0, sizeof (temp)); + temp.type = gimple_call_return_type (call); + temp.opcode = CALL_EXPR; + temp.op0 = gimple_call_fn (call); + temp.op1 = gimple_call_chain (call); + VEC_safe_push (vn_reference_op_s, heap, *result, &temp); + + /* Copy the call arguments. As they can be references as well, + just chain them together. */ + for (i = 0; i < gimple_call_num_args (call); ++i) + { + tree callarg = gimple_call_arg (call, i); + copy_reference_ops_from_ref (callarg, result); + } +} + +/* Create a vector of vn_reference_op_s structures from REF, a + REFERENCE_CLASS_P tree. The vector is not shared. */ + +static VEC(vn_reference_op_s, heap) * +create_reference_ops_from_ref (tree ref) +{ + VEC (vn_reference_op_s, heap) *result = NULL; + + copy_reference_ops_from_ref (ref, &result); + return result; +} + +/* Create a vector of vn_reference_op_s structures from CALL, a + call statement. The vector is not shared. */ + +static VEC(vn_reference_op_s, heap) * +create_reference_ops_from_call (gimple call) +{ + VEC (vn_reference_op_s, heap) *result = NULL; + + copy_reference_ops_from_call (call, &result); + return result; +} + +static VEC(vn_reference_op_s, heap) *shared_lookup_references; + +/* Create a vector of vn_reference_op_s structures from REF, a + REFERENCE_CLASS_P tree. The vector is shared among all callers of + this function. */ + +static VEC(vn_reference_op_s, heap) * +shared_reference_ops_from_ref (tree ref) +{ + if (!ref) + return NULL; + VEC_truncate (vn_reference_op_s, shared_lookup_references, 0); + copy_reference_ops_from_ref (ref, &shared_lookup_references); + return shared_lookup_references; +} + +/* Create a vector of vn_reference_op_s structures from CALL, a + call statement. The vector is shared among all callers of + this function. */ + +static VEC(vn_reference_op_s, heap) * +shared_reference_ops_from_call (gimple call) +{ + if (!call) + return NULL; + VEC_truncate (vn_reference_op_s, shared_lookup_references, 0); + copy_reference_ops_from_call (call, &shared_lookup_references); + return shared_lookup_references; +} + + +/* Transform any SSA_NAME's in a vector of vn_reference_op_s + structures into their value numbers. This is done in-place, and + the vector passed in is returned. */ + +static VEC (vn_reference_op_s, heap) * +valueize_refs (VEC (vn_reference_op_s, heap) *orig) +{ + vn_reference_op_t vro; + int i; + + for (i = 0; VEC_iterate (vn_reference_op_s, orig, i, vro); i++) + { + if (vro->opcode == SSA_NAME + || (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)) + { + vro->op0 = SSA_VAL (vro->op0); + /* If it transforms from an SSA_NAME to a constant, update + the opcode. */ + if (TREE_CODE (vro->op0) != SSA_NAME && vro->opcode == SSA_NAME) + vro->opcode = TREE_CODE (vro->op0); + } + /* TODO: Do we want to valueize op2 and op1 of + ARRAY_REF/COMPONENT_REF for Ada */ + + } + + return orig; +} + +/* Transform any SSA_NAME's in ORIG, a vector of vuse trees, into + their value numbers. This is done in-place, and the vector passed + in is returned. */ + +static VEC (tree, gc) * +valueize_vuses (VEC (tree, gc) *orig) +{ + bool made_replacement = false; + tree vuse; + int i; + + for (i = 0; VEC_iterate (tree, orig, i, vuse); i++) + { + if (vuse != SSA_VAL (vuse)) + { + made_replacement = true; + VEC_replace (tree, orig, i, SSA_VAL (vuse)); + } + } + + if (made_replacement && VEC_length (tree, orig) > 1) + sort_vuses (orig); + + return orig; +} + +/* Return the single reference statement defining all virtual uses + in VUSES or NULL_TREE, if there are multiple defining statements. + Take into account only definitions that alias REF if following + back-edges. */ + +static gimple +get_def_ref_stmt_vuses (tree ref, VEC (tree, gc) *vuses) +{ + gimple def_stmt; + tree vuse; + unsigned int i; + + gcc_assert (VEC_length (tree, vuses) >= 1); + + def_stmt = SSA_NAME_DEF_STMT (VEC_index (tree, vuses, 0)); + if (gimple_code (def_stmt) == GIMPLE_PHI) + { + /* We can only handle lookups over PHI nodes for a single + virtual operand. */ + if (VEC_length (tree, vuses) == 1) + { + def_stmt = get_single_def_stmt_from_phi (ref, def_stmt); + goto cont; + } + else + return NULL; + } + + /* Verify each VUSE reaches the same defining stmt. */ + for (i = 1; VEC_iterate (tree, vuses, i, vuse); ++i) + { + gimple tmp = SSA_NAME_DEF_STMT (vuse); + if (tmp != def_stmt) + return NULL; + } + + /* Now see if the definition aliases ref, and loop until it does. */ +cont: + while (def_stmt + && is_gimple_assign (def_stmt) + && !refs_may_alias_p (ref, gimple_get_lhs (def_stmt))) + def_stmt = get_single_def_stmt_with_phi (ref, def_stmt); + + return def_stmt; +} + +/* Lookup a SCCVN reference operation VR in the current hash table. + Returns the resulting value number if it exists in the hash table, + NULL_TREE otherwise. VNRESULT will be filled in with the actual + vn_reference_t stored in the hashtable if something is found. */ + +static tree +vn_reference_lookup_1 (vn_reference_t vr, vn_reference_t *vnresult) +{ + void **slot; + hashval_t hash; + + hash = vr->hashcode; + slot = htab_find_slot_with_hash (current_info->references, vr, + hash, NO_INSERT); + if (!slot && current_info == optimistic_info) + slot = htab_find_slot_with_hash (valid_info->references, vr, + hash, NO_INSERT); + if (slot) + { + if (vnresult) + *vnresult = (vn_reference_t)*slot; + return ((vn_reference_t)*slot)->result; + } + + return NULL_TREE; +} + + +/* Lookup a reference operation by it's parts, in the current hash table. + Returns the resulting value number if it exists in the hash table, + NULL_TREE otherwise. VNRESULT will be filled in with the actual + vn_reference_t stored in the hashtable if something is found. */ + +tree +vn_reference_lookup_pieces (VEC (tree, gc) *vuses, + VEC (vn_reference_op_s, heap) *operands, + vn_reference_t *vnresult, bool maywalk) +{ + struct vn_reference_s vr1; + tree result; + if (vnresult) + *vnresult = NULL; + + vr1.vuses = valueize_vuses (vuses); + vr1.operands = valueize_refs (operands); + vr1.hashcode = vn_reference_compute_hash (&vr1); + result = vn_reference_lookup_1 (&vr1, vnresult); + + /* If there is a single defining statement for all virtual uses, we can + use that, following virtual use-def chains. */ + if (!result + && maywalk + && vr1.vuses + && VEC_length (tree, vr1.vuses) >= 1) + { + tree ref = get_ref_from_reference_ops (operands); + gimple def_stmt; + if (ref + && (def_stmt = get_def_ref_stmt_vuses (ref, vr1.vuses)) + && is_gimple_assign (def_stmt)) + { + /* We are now at an aliasing definition for the vuses we want to + look up. Re-do the lookup with the vdefs for this stmt. */ + vdefs_to_vec (def_stmt, &vuses); + vr1.vuses = valueize_vuses (vuses); + vr1.hashcode = vn_reference_compute_hash (&vr1); + result = vn_reference_lookup_1 (&vr1, vnresult); + } + } + + return result; +} + +/* Lookup OP in the current hash table, and return the resulting value + number if it exists in the hash table. Return NULL_TREE if it does + not exist in the hash table or if the result field of the structure + was NULL.. VNRESULT will be filled in with the vn_reference_t + stored in the hashtable if one exists. */ + +tree +vn_reference_lookup (tree op, VEC (tree, gc) *vuses, bool maywalk, + vn_reference_t *vnresult) +{ + struct vn_reference_s vr1; + tree result; + gimple def_stmt; + if (vnresult) + *vnresult = NULL; + + vr1.vuses = valueize_vuses (vuses); + vr1.operands = valueize_refs (shared_reference_ops_from_ref (op)); + vr1.hashcode = vn_reference_compute_hash (&vr1); + result = vn_reference_lookup_1 (&vr1, vnresult); + + /* If there is a single defining statement for all virtual uses, we can + use that, following virtual use-def chains. */ + if (!result + && maywalk + && vr1.vuses + && VEC_length (tree, vr1.vuses) >= 1 + && (def_stmt = get_def_ref_stmt_vuses (op, vr1.vuses)) + && is_gimple_assign (def_stmt)) + { + /* We are now at an aliasing definition for the vuses we want to + look up. Re-do the lookup with the vdefs for this stmt. */ + vdefs_to_vec (def_stmt, &vuses); + vr1.vuses = valueize_vuses (vuses); + vr1.hashcode = vn_reference_compute_hash (&vr1); + result = vn_reference_lookup_1 (&vr1, vnresult); + } + + return result; +} + + +/* Insert OP into the current hash table with a value number of + RESULT, and return the resulting reference structure we created. */ + +vn_reference_t +vn_reference_insert (tree op, tree result, VEC (tree, gc) *vuses) +{ + void **slot; + vn_reference_t vr1; + + vr1 = (vn_reference_t) pool_alloc (current_info->references_pool); + if (TREE_CODE (result) == SSA_NAME) + vr1->value_id = VN_INFO (result)->value_id; + else + vr1->value_id = get_or_alloc_constant_value_id (result); + vr1->vuses = valueize_vuses (vuses); + vr1->operands = valueize_refs (create_reference_ops_from_ref (op)); + vr1->hashcode = vn_reference_compute_hash (vr1); + vr1->result = TREE_CODE (result) == SSA_NAME ? SSA_VAL (result) : result; + + slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode, + INSERT); + + /* Because we lookup stores using vuses, and value number failures + using the vdefs (see visit_reference_op_store for how and why), + it's possible that on failure we may try to insert an already + inserted store. This is not wrong, there is no ssa name for a + store that we could use as a differentiator anyway. Thus, unlike + the other lookup functions, you cannot gcc_assert (!*slot) + here. */ + + /* But free the old slot in case of a collision. */ + if (*slot) + free_reference (*slot); + + *slot = vr1; + return vr1; +} + +/* Insert a reference by it's pieces into the current hash table with + a value number of RESULT. Return the resulting reference + structure we created. */ + +vn_reference_t +vn_reference_insert_pieces (VEC (tree, gc) *vuses, + VEC (vn_reference_op_s, heap) *operands, + tree result, unsigned int value_id) + +{ + void **slot; + vn_reference_t vr1; + + vr1 = (vn_reference_t) pool_alloc (current_info->references_pool); + vr1->value_id = value_id; + vr1->vuses = valueize_vuses (vuses); + vr1->operands = valueize_refs (operands); + vr1->hashcode = vn_reference_compute_hash (vr1); + if (result && TREE_CODE (result) == SSA_NAME) + result = SSA_VAL (result); + vr1->result = result; + + slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode, + INSERT); + + /* At this point we should have all the things inserted that we have + seen before, and we should never try inserting something that + already exists. */ + gcc_assert (!*slot); + if (*slot) + free_reference (*slot); + + *slot = vr1; + return vr1; +} + +/* Compute and return the hash value for nary operation VBO1. */ + +inline hashval_t +vn_nary_op_compute_hash (const vn_nary_op_t vno1) +{ + hashval_t hash = 0; + unsigned i; + + for (i = 0; i < vno1->length; ++i) + if (TREE_CODE (vno1->op[i]) == SSA_NAME) + vno1->op[i] = SSA_VAL (vno1->op[i]); + + if (vno1->length == 2 + && commutative_tree_code (vno1->opcode) + && tree_swap_operands_p (vno1->op[0], vno1->op[1], false)) + { + tree temp = vno1->op[0]; + vno1->op[0] = vno1->op[1]; + vno1->op[1] = temp; + } + + for (i = 0; i < vno1->length; ++i) + hash += iterative_hash_expr (vno1->op[i], vno1->opcode); + + return hash; +} + +/* Return the computed hashcode for nary operation P1. */ + +static hashval_t +vn_nary_op_hash (const void *p1) +{ + const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1; + return vno1->hashcode; +} + +/* Compare nary operations P1 and P2 and return true if they are + equivalent. */ + +int +vn_nary_op_eq (const void *p1, const void *p2) +{ + const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1; + const_vn_nary_op_t const vno2 = (const_vn_nary_op_t) p2; + unsigned i; + + if (vno1->hashcode != vno2->hashcode) + return false; + + if (vno1->opcode != vno2->opcode + || !types_compatible_p (vno1->type, vno2->type)) + return false; + + for (i = 0; i < vno1->length; ++i) + if (!expressions_equal_p (vno1->op[i], vno2->op[i])) + return false; + + return true; +} + +/* Lookup a n-ary operation by its pieces and return the resulting value + number if it exists in the hash table. Return NULL_TREE if it does + not exist in the hash table or if the result field of the operation + is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable + if it exists. */ + +tree +vn_nary_op_lookup_pieces (unsigned int length, enum tree_code code, + tree type, tree op0, tree op1, tree op2, + tree op3, vn_nary_op_t *vnresult) +{ + void **slot; + struct vn_nary_op_s vno1; + if (vnresult) + *vnresult = NULL; + vno1.opcode = code; + vno1.length = length; + vno1.type = type; + vno1.op[0] = op0; + vno1.op[1] = op1; + vno1.op[2] = op2; + vno1.op[3] = op3; + vno1.hashcode = vn_nary_op_compute_hash (&vno1); + slot = htab_find_slot_with_hash (current_info->nary, &vno1, vno1.hashcode, + NO_INSERT); + if (!slot && current_info == optimistic_info) + slot = htab_find_slot_with_hash (valid_info->nary, &vno1, vno1.hashcode, + NO_INSERT); + if (!slot) + return NULL_TREE; + if (vnresult) + *vnresult = (vn_nary_op_t)*slot; + return ((vn_nary_op_t)*slot)->result; +} + +/* Lookup OP in the current hash table, and return the resulting value + number if it exists in the hash table. Return NULL_TREE if it does + not exist in the hash table or if the result field of the operation + is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable + if it exists. */ + +tree +vn_nary_op_lookup (tree op, vn_nary_op_t *vnresult) +{ + void **slot; + struct vn_nary_op_s vno1; + unsigned i; + + if (vnresult) + *vnresult = NULL; + vno1.opcode = TREE_CODE (op); + vno1.length = TREE_CODE_LENGTH (TREE_CODE (op)); + vno1.type = TREE_TYPE (op); + for (i = 0; i < vno1.length; ++i) + vno1.op[i] = TREE_OPERAND (op, i); + vno1.hashcode = vn_nary_op_compute_hash (&vno1); + slot = htab_find_slot_with_hash (current_info->nary, &vno1, vno1.hashcode, + NO_INSERT); + if (!slot && current_info == optimistic_info) + slot = htab_find_slot_with_hash (valid_info->nary, &vno1, vno1.hashcode, + NO_INSERT); + if (!slot) + return NULL_TREE; + if (vnresult) + *vnresult = (vn_nary_op_t)*slot; + return ((vn_nary_op_t)*slot)->result; +} + +/* Lookup the rhs of STMT in the current hash table, and return the resulting + value number if it exists in the hash table. Return NULL_TREE if + it does not exist in the hash table. VNRESULT will contain the + vn_nary_op_t from the hashtable if it exists. */ + +tree +vn_nary_op_lookup_stmt (gimple stmt, vn_nary_op_t *vnresult) +{ + void **slot; + struct vn_nary_op_s vno1; + unsigned i; + + if (vnresult) + *vnresult = NULL; + vno1.opcode = gimple_assign_rhs_code (stmt); + vno1.length = gimple_num_ops (stmt) - 1; + vno1.type = gimple_expr_type (stmt); + for (i = 0; i < vno1.length; ++i) + vno1.op[i] = gimple_op (stmt, i + 1); + if (vno1.opcode == REALPART_EXPR + || vno1.opcode == IMAGPART_EXPR + || vno1.opcode == VIEW_CONVERT_EXPR) + vno1.op[0] = TREE_OPERAND (vno1.op[0], 0); + vno1.hashcode = vn_nary_op_compute_hash (&vno1); + slot = htab_find_slot_with_hash (current_info->nary, &vno1, vno1.hashcode, + NO_INSERT); + if (!slot && current_info == optimistic_info) + slot = htab_find_slot_with_hash (valid_info->nary, &vno1, vno1.hashcode, + NO_INSERT); + if (!slot) + return NULL_TREE; + if (vnresult) + *vnresult = (vn_nary_op_t)*slot; + return ((vn_nary_op_t)*slot)->result; +} + +/* Insert a n-ary operation into the current hash table using it's + pieces. Return the vn_nary_op_t structure we created and put in + the hashtable. */ + +vn_nary_op_t +vn_nary_op_insert_pieces (unsigned int length, enum tree_code code, + tree type, tree op0, + tree op1, tree op2, tree op3, + tree result, + unsigned int value_id) +{ + void **slot; + vn_nary_op_t vno1; + + vno1 = (vn_nary_op_t) obstack_alloc (¤t_info->nary_obstack, + (sizeof (struct vn_nary_op_s) + - sizeof (tree) * (4 - length))); + vno1->value_id = value_id; + vno1->opcode = code; + vno1->length = length; + vno1->type = type; + if (length >= 1) + vno1->op[0] = op0; + if (length >= 2) + vno1->op[1] = op1; + if (length >= 3) + vno1->op[2] = op2; + if (length >= 4) + vno1->op[3] = op3; + vno1->result = result; + vno1->hashcode = vn_nary_op_compute_hash (vno1); + slot = htab_find_slot_with_hash (current_info->nary, vno1, vno1->hashcode, + INSERT); + gcc_assert (!*slot); + + *slot = vno1; + return vno1; + +} + +/* Insert OP into the current hash table with a value number of + RESULT. Return the vn_nary_op_t structure we created and put in + the hashtable. */ + +vn_nary_op_t +vn_nary_op_insert (tree op, tree result) +{ + unsigned length = TREE_CODE_LENGTH (TREE_CODE (op)); + void **slot; + vn_nary_op_t vno1; + unsigned i; + + vno1 = (vn_nary_op_t) obstack_alloc (¤t_info->nary_obstack, + (sizeof (struct vn_nary_op_s) + - sizeof (tree) * (4 - length))); + vno1->value_id = VN_INFO (result)->value_id; + vno1->opcode = TREE_CODE (op); + vno1->length = length; + vno1->type = TREE_TYPE (op); + for (i = 0; i < vno1->length; ++i) + vno1->op[i] = TREE_OPERAND (op, i); + vno1->result = result; + vno1->hashcode = vn_nary_op_compute_hash (vno1); + slot = htab_find_slot_with_hash (current_info->nary, vno1, vno1->hashcode, + INSERT); + gcc_assert (!*slot); + + *slot = vno1; + return vno1; +} + +/* Insert the rhs of STMT into the current hash table with a value number of + RESULT. */ + +vn_nary_op_t +vn_nary_op_insert_stmt (gimple stmt, tree result) +{ + unsigned length = gimple_num_ops (stmt) - 1; + void **slot; + vn_nary_op_t vno1; + unsigned i; + + vno1 = (vn_nary_op_t) obstack_alloc (¤t_info->nary_obstack, + (sizeof (struct vn_nary_op_s) + - sizeof (tree) * (4 - length))); + vno1->value_id = VN_INFO (result)->value_id; + vno1->opcode = gimple_assign_rhs_code (stmt); + vno1->length = length; + vno1->type = gimple_expr_type (stmt); + for (i = 0; i < vno1->length; ++i) + vno1->op[i] = gimple_op (stmt, i + 1); + if (vno1->opcode == REALPART_EXPR + || vno1->opcode == IMAGPART_EXPR + || vno1->opcode == VIEW_CONVERT_EXPR) + vno1->op[0] = TREE_OPERAND (vno1->op[0], 0); + vno1->result = result; + vno1->hashcode = vn_nary_op_compute_hash (vno1); + slot = htab_find_slot_with_hash (current_info->nary, vno1, vno1->hashcode, + INSERT); + gcc_assert (!*slot); + + *slot = vno1; + return vno1; +} + +/* Compute a hashcode for PHI operation VP1 and return it. */ + +static inline hashval_t +vn_phi_compute_hash (vn_phi_t vp1) +{ + hashval_t result = 0; + int i; + tree phi1op; + tree type; + + result = vp1->block->index; + + /* If all PHI arguments are constants we need to distinguish + the PHI node via its type. */ + type = TREE_TYPE (VEC_index (tree, vp1->phiargs, 0)); + result += (INTEGRAL_TYPE_P (type) + + (INTEGRAL_TYPE_P (type) + ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0)); + + for (i = 0; VEC_iterate (tree, vp1->phiargs, i, phi1op); i++) + { + if (phi1op == VN_TOP) + continue; + result += iterative_hash_expr (phi1op, result); + } + + return result; +} + +/* Return the computed hashcode for phi operation P1. */ + +static hashval_t +vn_phi_hash (const void *p1) +{ + const_vn_phi_t const vp1 = (const_vn_phi_t) p1; + return vp1->hashcode; +} + +/* Compare two phi entries for equality, ignoring VN_TOP arguments. */ + +static int +vn_phi_eq (const void *p1, const void *p2) +{ + const_vn_phi_t const vp1 = (const_vn_phi_t) p1; + const_vn_phi_t const vp2 = (const_vn_phi_t) p2; + + if (vp1->hashcode != vp2->hashcode) + return false; + + if (vp1->block == vp2->block) + { + int i; + tree phi1op; + + /* If the PHI nodes do not have compatible types + they are not the same. */ + if (!types_compatible_p (TREE_TYPE (VEC_index (tree, vp1->phiargs, 0)), + TREE_TYPE (VEC_index (tree, vp2->phiargs, 0)))) + return false; + + /* Any phi in the same block will have it's arguments in the + same edge order, because of how we store phi nodes. */ + for (i = 0; VEC_iterate (tree, vp1->phiargs, i, phi1op); i++) + { + tree phi2op = VEC_index (tree, vp2->phiargs, i); + if (phi1op == VN_TOP || phi2op == VN_TOP) + continue; + if (!expressions_equal_p (phi1op, phi2op)) + return false; + } + return true; + } + return false; +} + +static VEC(tree, heap) *shared_lookup_phiargs; + +/* Lookup PHI in the current hash table, and return the resulting + value number if it exists in the hash table. Return NULL_TREE if + it does not exist in the hash table. */ + +static tree +vn_phi_lookup (gimple phi) +{ + void **slot; + struct vn_phi_s vp1; + unsigned i; + + VEC_truncate (tree, shared_lookup_phiargs, 0); + + /* Canonicalize the SSA_NAME's to their value number. */ + for (i = 0; i < gimple_phi_num_args (phi); i++) + { + tree def = PHI_ARG_DEF (phi, i); + def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def; + VEC_safe_push (tree, heap, shared_lookup_phiargs, def); + } + vp1.phiargs = shared_lookup_phiargs; + vp1.block = gimple_bb (phi); + vp1.hashcode = vn_phi_compute_hash (&vp1); + slot = htab_find_slot_with_hash (current_info->phis, &vp1, vp1.hashcode, + NO_INSERT); + if (!slot && current_info == optimistic_info) + slot = htab_find_slot_with_hash (valid_info->phis, &vp1, vp1.hashcode, + NO_INSERT); + if (!slot) + return NULL_TREE; + return ((vn_phi_t)*slot)->result; +} + +/* Insert PHI into the current hash table with a value number of + RESULT. */ + +static vn_phi_t +vn_phi_insert (gimple phi, tree result) +{ + void **slot; + vn_phi_t vp1 = (vn_phi_t) pool_alloc (current_info->phis_pool); + unsigned i; + VEC (tree, heap) *args = NULL; + + /* Canonicalize the SSA_NAME's to their value number. */ + for (i = 0; i < gimple_phi_num_args (phi); i++) + { + tree def = PHI_ARG_DEF (phi, i); + def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def; + VEC_safe_push (tree, heap, args, def); + } + vp1->value_id = VN_INFO (result)->value_id; + vp1->phiargs = args; + vp1->block = gimple_bb (phi); + vp1->result = result; + vp1->hashcode = vn_phi_compute_hash (vp1); + + slot = htab_find_slot_with_hash (current_info->phis, vp1, vp1->hashcode, + INSERT); + + /* Because we iterate over phi operations more than once, it's + possible the slot might already exist here, hence no assert.*/ + *slot = vp1; + return vp1; +} + + +/* Print set of components in strongly connected component SCC to OUT. */ + +static void +print_scc (FILE *out, VEC (tree, heap) *scc) +{ + tree var; + unsigned int i; + + fprintf (out, "SCC consists of: "); + for (i = 0; VEC_iterate (tree, scc, i, var); i++) + { + print_generic_expr (out, var, 0); + fprintf (out, " "); + } + fprintf (out, "\n"); +} + +/* Set the value number of FROM to TO, return true if it has changed + as a result. */ + +static inline bool +set_ssa_val_to (tree from, tree to) +{ + tree currval; + + if (from != to + && TREE_CODE (to) == SSA_NAME + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (to)) + to = from; + + /* The only thing we allow as value numbers are VN_TOP, ssa_names + and invariants. So assert that here. */ + gcc_assert (to != NULL_TREE + && (to == VN_TOP + || TREE_CODE (to) == SSA_NAME + || is_gimple_min_invariant (to))); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Setting value number of "); + print_generic_expr (dump_file, from, 0); + fprintf (dump_file, " to "); + print_generic_expr (dump_file, to, 0); + } + + currval = SSA_VAL (from); + + if (currval != to && !operand_equal_p (currval, to, OEP_PURE_SAME)) + { + SSA_VAL (from) = to; + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, " (changed)\n"); + return true; + } + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\n"); + return false; +} + +/* Set all definitions in STMT to value number to themselves. + Return true if a value number changed. */ + +static bool +defs_to_varying (gimple stmt) +{ + bool changed = false; + ssa_op_iter iter; + def_operand_p defp; + + FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_ALL_DEFS) + { + tree def = DEF_FROM_PTR (defp); + + VN_INFO (def)->use_processed = true; + changed |= set_ssa_val_to (def, def); + } + return changed; +} + +static bool expr_has_constants (tree expr); +static tree valueize_expr (tree expr); + +/* Visit a copy between LHS and RHS, return true if the value number + changed. */ + +static bool +visit_copy (tree lhs, tree rhs) +{ + /* Follow chains of copies to their destination. */ + while (TREE_CODE (rhs) == SSA_NAME + && SSA_VAL (rhs) != rhs) + rhs = SSA_VAL (rhs); + + /* The copy may have a more interesting constant filled expression + (we don't, since we know our RHS is just an SSA name). */ + if (TREE_CODE (rhs) == SSA_NAME) + { + VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants; + VN_INFO (lhs)->expr = VN_INFO (rhs)->expr; + } + + return set_ssa_val_to (lhs, rhs); +} + +/* Visit a unary operator RHS, value number it, and return true if the + value number of LHS has changed as a result. */ + +static bool +visit_unary_op (tree lhs, gimple stmt) +{ + bool changed = false; + tree result = vn_nary_op_lookup_stmt (stmt, NULL); + + if (result) + { + changed = set_ssa_val_to (lhs, result); + } + else + { + changed = set_ssa_val_to (lhs, lhs); + vn_nary_op_insert_stmt (stmt, lhs); + } + + return changed; +} + +/* Visit a binary operator RHS, value number it, and return true if the + value number of LHS has changed as a result. */ + +static bool +visit_binary_op (tree lhs, gimple stmt) +{ + bool changed = false; + tree result = vn_nary_op_lookup_stmt (stmt, NULL); + + if (result) + { + changed = set_ssa_val_to (lhs, result); + } + else + { + changed = set_ssa_val_to (lhs, lhs); + vn_nary_op_insert_stmt (stmt, lhs); + } + + return changed; +} + +/* Visit a call STMT storing into LHS. Return true if the value number + of the LHS has changed as a result. */ + +static bool +visit_reference_op_call (tree lhs, gimple stmt) +{ + bool changed = false; + struct vn_reference_s vr1; + tree result; + + vr1.vuses = valueize_vuses (shared_vuses_from_stmt (stmt)); + vr1.operands = valueize_refs (shared_reference_ops_from_call (stmt)); + vr1.hashcode = vn_reference_compute_hash (&vr1); + result = vn_reference_lookup_1 (&vr1, NULL); + if (result) + { + changed = set_ssa_val_to (lhs, result); + if (TREE_CODE (result) == SSA_NAME + && VN_INFO (result)->has_constants) + VN_INFO (lhs)->has_constants = true; + } + else + { + void **slot; + vn_reference_t vr2; + changed = set_ssa_val_to (lhs, lhs); + vr2 = (vn_reference_t) pool_alloc (current_info->references_pool); + vr2->vuses = valueize_vuses (copy_vuses_from_stmt (stmt)); + vr2->operands = valueize_refs (create_reference_ops_from_call (stmt)); + vr2->hashcode = vr1.hashcode; + vr2->result = lhs; + slot = htab_find_slot_with_hash (current_info->references, + vr2, vr2->hashcode, INSERT); + if (*slot) + free_reference (*slot); + *slot = vr2; + } + + return changed; +} + +/* Visit a load from a reference operator RHS, part of STMT, value number it, + and return true if the value number of the LHS has changed as a result. */ + +static bool +visit_reference_op_load (tree lhs, tree op, gimple stmt) +{ + bool changed = false; + tree result = vn_reference_lookup (op, shared_vuses_from_stmt (stmt), true, + NULL); + + /* We handle type-punning through unions by value-numbering based + on offset and size of the access. Be prepared to handle a + type-mismatch here via creating a VIEW_CONVERT_EXPR. */ + if (result + && !useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (op))) + { + /* We will be setting the value number of lhs to the value number + of VIEW_CONVERT_EXPR (result). + So first simplify and lookup this expression to see if it + is already available. */ + tree val = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (op), result); + if ((CONVERT_EXPR_P (val) + || TREE_CODE (val) == VIEW_CONVERT_EXPR) + && TREE_CODE (TREE_OPERAND (val, 0)) == SSA_NAME) + { + tree tem = valueize_expr (vn_get_expr_for (TREE_OPERAND (val, 0))); + if ((CONVERT_EXPR_P (tem) + || TREE_CODE (tem) == VIEW_CONVERT_EXPR) + && (tem = fold_unary_ignore_overflow (TREE_CODE (val), + TREE_TYPE (val), tem))) + val = tem; + } + result = val; + if (!is_gimple_min_invariant (val) + && TREE_CODE (val) != SSA_NAME) + result = vn_nary_op_lookup (val, NULL); + /* If the expression is not yet available, value-number lhs to + a new SSA_NAME we create. */ + if (!result && may_insert) + { + result = make_ssa_name (SSA_NAME_VAR (lhs), NULL); + /* Initialize value-number information properly. */ + VN_INFO_GET (result)->valnum = result; + VN_INFO (result)->value_id = get_next_value_id (); + VN_INFO (result)->expr = val; + VN_INFO (result)->has_constants = expr_has_constants (val); + VN_INFO (result)->needs_insertion = true; + /* As all "inserted" statements are singleton SCCs, insert + to the valid table. This is strictly needed to + avoid re-generating new value SSA_NAMEs for the same + expression during SCC iteration over and over (the + optimistic table gets cleared after each iteration). + We do not need to insert into the optimistic table, as + lookups there will fall back to the valid table. */ + if (current_info == optimistic_info) + { + current_info = valid_info; + vn_nary_op_insert (val, result); + current_info = optimistic_info; + } + else + vn_nary_op_insert (val, result); + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Inserting name "); + print_generic_expr (dump_file, result, 0); + fprintf (dump_file, " for expression "); + print_generic_expr (dump_file, val, 0); + fprintf (dump_file, "\n"); + } + } + } + + if (result) + { + changed = set_ssa_val_to (lhs, result); + if (TREE_CODE (result) == SSA_NAME + && VN_INFO (result)->has_constants) + { + VN_INFO (lhs)->expr = VN_INFO (result)->expr; + VN_INFO (lhs)->has_constants = true; + } + } + else + { + changed = set_ssa_val_to (lhs, lhs); + vn_reference_insert (op, lhs, copy_vuses_from_stmt (stmt)); + } + + return changed; +} + + +/* Visit a store to a reference operator LHS, part of STMT, value number it, + and return true if the value number of the LHS has changed as a result. */ + +static bool +visit_reference_op_store (tree lhs, tree op, gimple stmt) +{ + bool changed = false; + tree result; + bool resultsame = false; + + /* First we want to lookup using the *vuses* from the store and see + if there the last store to this location with the same address + had the same value. + + The vuses represent the memory state before the store. If the + memory state, address, and value of the store is the same as the + last store to this location, then this store will produce the + same memory state as that store. + + In this case the vdef versions for this store are value numbered to those + vuse versions, since they represent the same memory state after + this store. + + Otherwise, the vdefs for the store are used when inserting into + the table, since the store generates a new memory state. */ + + result = vn_reference_lookup (lhs, shared_vuses_from_stmt (stmt), false, + NULL); + + if (result) + { + if (TREE_CODE (result) == SSA_NAME) + result = SSA_VAL (result); + if (TREE_CODE (op) == SSA_NAME) + op = SSA_VAL (op); + resultsame = expressions_equal_p (result, op); + } + + if (!result || !resultsame) + { + VEC(tree, gc) *vdefs = copy_vdefs_from_stmt (stmt); + int i; + tree vdef; + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "No store match\n"); + fprintf (dump_file, "Value numbering store "); + print_generic_expr (dump_file, lhs, 0); + fprintf (dump_file, " to "); + print_generic_expr (dump_file, op, 0); + fprintf (dump_file, "\n"); + } + /* Have to set value numbers before insert, since insert is + going to valueize the references in-place. */ + for (i = 0; VEC_iterate (tree, vdefs, i, vdef); i++) + { + VN_INFO (vdef)->use_processed = true; + changed |= set_ssa_val_to (vdef, vdef); + } + + /* Do not insert structure copies into the tables. */ + if (is_gimple_min_invariant (op) + || is_gimple_reg (op)) + vn_reference_insert (lhs, op, vdefs); + } + else + { + /* We had a match, so value number the vdefs to have the value + number of the vuses they came from. */ + ssa_op_iter op_iter; + def_operand_p var; + vuse_vec_p vv; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Store matched earlier value," + "value numbering store vdefs to matching vuses.\n"); + + FOR_EACH_SSA_VDEF_OPERAND (var, vv, stmt, op_iter) + { + tree def = DEF_FROM_PTR (var); + tree use; + + /* Uh, if the vuse is a multiuse, we can't really do much + here, sadly, since we don't know which value number of + which vuse to use. */ + if (VUSE_VECT_NUM_ELEM (*vv) != 1) + use = def; + else + use = VUSE_ELEMENT_VAR (*vv, 0); + + VN_INFO (def)->use_processed = true; + changed |= set_ssa_val_to (def, SSA_VAL (use)); + } + } + + return changed; +} + +/* Visit and value number PHI, return true if the value number + changed. */ + +static bool +visit_phi (gimple phi) +{ + bool changed = false; + tree result; + tree sameval = VN_TOP; + bool allsame = true; + unsigned i; + + /* TODO: We could check for this in init_sccvn, and replace this + with a gcc_assert. */ + if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi))) + return set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi)); + + /* See if all non-TOP arguments have the same value. TOP is + equivalent to everything, so we can ignore it. */ + for (i = 0; i < gimple_phi_num_args (phi); i++) + { + tree def = PHI_ARG_DEF (phi, i); + + if (TREE_CODE (def) == SSA_NAME) + def = SSA_VAL (def); + if (def == VN_TOP) + continue; + if (sameval == VN_TOP) + { + sameval = def; + } + else + { + if (!expressions_equal_p (def, sameval)) + { + allsame = false; + break; + } + } + } + + /* If all value numbered to the same value, the phi node has that + value. */ + if (allsame) + { + if (is_gimple_min_invariant (sameval)) + { + VN_INFO (PHI_RESULT (phi))->has_constants = true; + VN_INFO (PHI_RESULT (phi))->expr = sameval; + } + else + { + VN_INFO (PHI_RESULT (phi))->has_constants = false; + VN_INFO (PHI_RESULT (phi))->expr = sameval; + } + + if (TREE_CODE (sameval) == SSA_NAME) + return visit_copy (PHI_RESULT (phi), sameval); + + return set_ssa_val_to (PHI_RESULT (phi), sameval); + } + + /* Otherwise, see if it is equivalent to a phi node in this block. */ + result = vn_phi_lookup (phi); + if (result) + { + if (TREE_CODE (result) == SSA_NAME) + changed = visit_copy (PHI_RESULT (phi), result); + else + changed = set_ssa_val_to (PHI_RESULT (phi), result); + } + else + { + vn_phi_insert (phi, PHI_RESULT (phi)); + VN_INFO (PHI_RESULT (phi))->has_constants = false; + VN_INFO (PHI_RESULT (phi))->expr = PHI_RESULT (phi); + changed = set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi)); + } + + return changed; +} + +/* Return true if EXPR contains constants. */ + +static bool +expr_has_constants (tree expr) +{ + switch (TREE_CODE_CLASS (TREE_CODE (expr))) + { + case tcc_unary: + return is_gimple_min_invariant (TREE_OPERAND (expr, 0)); + + case tcc_binary: + return is_gimple_min_invariant (TREE_OPERAND (expr, 0)) + || is_gimple_min_invariant (TREE_OPERAND (expr, 1)); + /* Constants inside reference ops are rarely interesting, but + it can take a lot of looking to find them. */ + case tcc_reference: + case tcc_declaration: + return false; + default: + return is_gimple_min_invariant (expr); + } + return false; +} + +/* Return true if STMT contains constants. */ + +static bool +stmt_has_constants (gimple stmt) +{ + if (gimple_code (stmt) != GIMPLE_ASSIGN) + return false; + + switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt))) + { + case GIMPLE_UNARY_RHS: + return is_gimple_min_invariant (gimple_assign_rhs1 (stmt)); + + case GIMPLE_BINARY_RHS: + return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt)) + || is_gimple_min_invariant (gimple_assign_rhs2 (stmt))); + case GIMPLE_SINGLE_RHS: + /* Constants inside reference ops are rarely interesting, but + it can take a lot of looking to find them. */ + return is_gimple_min_invariant (gimple_assign_rhs1 (stmt)); + default: + gcc_unreachable (); + } + return false; +} + +/* Replace SSA_NAMES in expr with their value numbers, and return the + result. + This is performed in place. */ + +static tree +valueize_expr (tree expr) +{ + switch (TREE_CODE_CLASS (TREE_CODE (expr))) + { + case tcc_unary: + if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME + && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP) + TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0)); + break; + case tcc_binary: + if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME + && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP) + TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0)); + if (TREE_CODE (TREE_OPERAND (expr, 1)) == SSA_NAME + && SSA_VAL (TREE_OPERAND (expr, 1)) != VN_TOP) + TREE_OPERAND (expr, 1) = SSA_VAL (TREE_OPERAND (expr, 1)); + break; + default: + break; + } + return expr; +} + +/* Simplify the binary expression RHS, and return the result if + simplified. */ + +static tree +simplify_binary_expression (gimple stmt) +{ + tree result = NULL_TREE; + tree op0 = gimple_assign_rhs1 (stmt); + tree op1 = gimple_assign_rhs2 (stmt); + + /* This will not catch every single case we could combine, but will + catch those with constants. The goal here is to simultaneously + combine constants between expressions, but avoid infinite + expansion of expressions during simplification. */ + if (TREE_CODE (op0) == SSA_NAME) + { + if (VN_INFO (op0)->has_constants + || TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison) + op0 = valueize_expr (vn_get_expr_for (op0)); + else if (SSA_VAL (op0) != VN_TOP && SSA_VAL (op0) != op0) + op0 = SSA_VAL (op0); + } + + if (TREE_CODE (op1) == SSA_NAME) + { + if (VN_INFO (op1)->has_constants) + op1 = valueize_expr (vn_get_expr_for (op1)); + else if (SSA_VAL (op1) != VN_TOP && SSA_VAL (op1) != op1) + op1 = SSA_VAL (op1); + } + + /* Avoid folding if nothing changed. */ + if (op0 == gimple_assign_rhs1 (stmt) + && op1 == gimple_assign_rhs2 (stmt)) + return NULL_TREE; + + fold_defer_overflow_warnings (); + + result = fold_binary (gimple_assign_rhs_code (stmt), + gimple_expr_type (stmt), op0, op1); + if (result) + STRIP_USELESS_TYPE_CONVERSION (result); + + fold_undefer_overflow_warnings (result && valid_gimple_rhs_p (result), + stmt, 0); + + /* Make sure result is not a complex expression consisting + of operators of operators (IE (a + b) + (a + c)) + Otherwise, we will end up with unbounded expressions if + fold does anything at all. */ + if (result && valid_gimple_rhs_p (result)) + return result; + + return NULL_TREE; +} + +/* Simplify the unary expression RHS, and return the result if + simplified. */ + +static tree +simplify_unary_expression (gimple stmt) +{ + tree result = NULL_TREE; + tree orig_op0, op0 = gimple_assign_rhs1 (stmt); + + /* We handle some tcc_reference codes here that are all + GIMPLE_ASSIGN_SINGLE codes. */ + if (gimple_assign_rhs_code (stmt) == REALPART_EXPR + || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR + || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR) + op0 = TREE_OPERAND (op0, 0); + + if (TREE_CODE (op0) != SSA_NAME) + return NULL_TREE; + + orig_op0 = op0; + if (VN_INFO (op0)->has_constants) + op0 = valueize_expr (vn_get_expr_for (op0)); + else if (gimple_assign_cast_p (stmt) + || gimple_assign_rhs_code (stmt) == REALPART_EXPR + || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR + || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR) + { + /* We want to do tree-combining on conversion-like expressions. + Make sure we feed only SSA_NAMEs or constants to fold though. */ + tree tem = valueize_expr (vn_get_expr_for (op0)); + if (UNARY_CLASS_P (tem) + || BINARY_CLASS_P (tem) + || TREE_CODE (tem) == VIEW_CONVERT_EXPR + || TREE_CODE (tem) == SSA_NAME + || is_gimple_min_invariant (tem)) + op0 = tem; + } + + /* Avoid folding if nothing changed, but remember the expression. */ + if (op0 == orig_op0) + return NULL_TREE; + + result = fold_unary_ignore_overflow (gimple_assign_rhs_code (stmt), + gimple_expr_type (stmt), op0); + if (result) + { + STRIP_USELESS_TYPE_CONVERSION (result); + if (valid_gimple_rhs_p (result)) + return result; + } + + return NULL_TREE; +} + +/* Try to simplify RHS using equivalences and constant folding. */ + +static tree +try_to_simplify (gimple stmt) +{ + tree tem; + + /* For stores we can end up simplifying a SSA_NAME rhs. Just return + in this case, there is no point in doing extra work. */ + if (gimple_assign_copy_p (stmt) + && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) + return NULL_TREE; + + switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt))) + { + case tcc_declaration: + tem = get_symbol_constant_value (gimple_assign_rhs1 (stmt)); + if (tem) + return tem; + break; + + case tcc_reference: + /* Do not do full-blown reference lookup here, but simplify + reads from constant aggregates. */ + tem = fold_const_aggregate_ref (gimple_assign_rhs1 (stmt)); + if (tem) + return tem; + + /* Fallthrough for some codes that can operate on registers. */ + if (!(TREE_CODE (gimple_assign_rhs1 (stmt)) == REALPART_EXPR + || TREE_CODE (gimple_assign_rhs1 (stmt)) == IMAGPART_EXPR + || TREE_CODE (gimple_assign_rhs1 (stmt)) == VIEW_CONVERT_EXPR)) + break; + /* We could do a little more with unary ops, if they expand + into binary ops, but it's debatable whether it is worth it. */ + case tcc_unary: + return simplify_unary_expression (stmt); + break; + case tcc_comparison: + case tcc_binary: + return simplify_binary_expression (stmt); + break; + default: + break; + } + + return NULL_TREE; +} + +/* Visit and value number USE, return true if the value number + changed. */ + +static bool +visit_use (tree use) +{ + bool changed = false; + gimple stmt = SSA_NAME_DEF_STMT (use); + + VN_INFO (use)->use_processed = true; + + gcc_assert (!SSA_NAME_IN_FREE_LIST (use)); + if (dump_file && (dump_flags & TDF_DETAILS) + && !SSA_NAME_IS_DEFAULT_DEF (use)) + { + fprintf (dump_file, "Value numbering "); + print_generic_expr (dump_file, use, 0); + fprintf (dump_file, " stmt = "); + print_gimple_stmt (dump_file, stmt, 0, 0); + } + + /* Handle uninitialized uses. */ + if (SSA_NAME_IS_DEFAULT_DEF (use)) + changed = set_ssa_val_to (use, use); + else + { + if (gimple_code (stmt) == GIMPLE_PHI) + changed = visit_phi (stmt); + else if (!gimple_has_lhs (stmt) + || gimple_has_volatile_ops (stmt) + || stmt_could_throw_p (stmt)) + changed = defs_to_varying (stmt); + else if (is_gimple_assign (stmt)) + { + tree lhs = gimple_assign_lhs (stmt); + tree simplified; + + /* Shortcut for copies. Simplifying copies is pointless, + since we copy the expression and value they represent. */ + if (gimple_assign_copy_p (stmt) + && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME + && TREE_CODE (lhs) == SSA_NAME) + { + changed = visit_copy (lhs, gimple_assign_rhs1 (stmt)); + goto done; + } + simplified = try_to_simplify (stmt); + if (simplified) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "RHS "); + print_gimple_expr (dump_file, stmt, 0, 0); + fprintf (dump_file, " simplified to "); + print_generic_expr (dump_file, simplified, 0); + if (TREE_CODE (lhs) == SSA_NAME) + fprintf (dump_file, " has constants %d\n", + expr_has_constants (simplified)); + else + fprintf (dump_file, "\n"); + } + } + /* Setting value numbers to constants will occasionally + screw up phi congruence because constants are not + uniquely associated with a single ssa name that can be + looked up. */ + if (simplified + && is_gimple_min_invariant (simplified) + && TREE_CODE (lhs) == SSA_NAME) + { + VN_INFO (lhs)->expr = simplified; + VN_INFO (lhs)->has_constants = true; + changed = set_ssa_val_to (lhs, simplified); + goto done; + } + else if (simplified + && TREE_CODE (simplified) == SSA_NAME + && TREE_CODE (lhs) == SSA_NAME) + { + changed = visit_copy (lhs, simplified); + goto done; + } + else if (simplified) + { + if (TREE_CODE (lhs) == SSA_NAME) + { + VN_INFO (lhs)->has_constants = expr_has_constants (simplified); + /* We have to unshare the expression or else + valuizing may change the IL stream. */ + VN_INFO (lhs)->expr = unshare_expr (simplified); + } + } + else if (stmt_has_constants (stmt) + && TREE_CODE (lhs) == SSA_NAME) + VN_INFO (lhs)->has_constants = true; + else if (TREE_CODE (lhs) == SSA_NAME) + { + /* We reset expr and constantness here because we may + have been value numbering optimistically, and + iterating. They may become non-constant in this case, + even if they were optimistically constant. */ + + VN_INFO (lhs)->has_constants = false; + VN_INFO (lhs)->expr = NULL_TREE; + } + + if ((TREE_CODE (lhs) == SSA_NAME + /* We can substitute SSA_NAMEs that are live over + abnormal edges with their constant value. */ + && !(gimple_assign_copy_p (stmt) + && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) + && !(simplified + && is_gimple_min_invariant (simplified)) + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) + /* Stores or copies from SSA_NAMEs that are live over + abnormal edges are a problem. */ + || (gimple_assign_single_p (stmt) + && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt)))) + changed = defs_to_varying (stmt); + else if (REFERENCE_CLASS_P (lhs) || DECL_P (lhs)) + { + changed = visit_reference_op_store (lhs, gimple_assign_rhs1 (stmt), stmt); + } + else if (TREE_CODE (lhs) == SSA_NAME) + { + if ((gimple_assign_copy_p (stmt) + && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) + || (simplified + && is_gimple_min_invariant (simplified))) + { + VN_INFO (lhs)->has_constants = true; + if (simplified) + changed = set_ssa_val_to (lhs, simplified); + else + changed = set_ssa_val_to (lhs, gimple_assign_rhs1 (stmt)); + } + else + { + switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt))) + { + case GIMPLE_UNARY_RHS: + changed = visit_unary_op (lhs, stmt); + break; + case GIMPLE_BINARY_RHS: + changed = visit_binary_op (lhs, stmt); + break; + case GIMPLE_SINGLE_RHS: + switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt))) + { + case tcc_reference: + /* VOP-less references can go through unary case. */ + if ((gimple_assign_rhs_code (stmt) == REALPART_EXPR + || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR + || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR ) + && TREE_CODE (TREE_OPERAND (gimple_assign_rhs1 (stmt), 0)) == SSA_NAME) + { + changed = visit_unary_op (lhs, stmt); + break; + } + /* Fallthrough. */ + case tcc_declaration: + changed = visit_reference_op_load + (lhs, gimple_assign_rhs1 (stmt), stmt); + break; + case tcc_expression: + if (gimple_assign_rhs_code (stmt) == ADDR_EXPR) + { + changed = visit_unary_op (lhs, stmt); + break; + } + /* Fallthrough. */ + default: + changed = defs_to_varying (stmt); + } + break; + default: + changed = defs_to_varying (stmt); + break; + } + } + } + else + changed = defs_to_varying (stmt); + } + else if (is_gimple_call (stmt)) + { + tree lhs = gimple_call_lhs (stmt); + + /* ??? We could try to simplify calls. */ + + if (stmt_has_constants (stmt) + && TREE_CODE (lhs) == SSA_NAME) + VN_INFO (lhs)->has_constants = true; + else if (TREE_CODE (lhs) == SSA_NAME) + { + /* We reset expr and constantness here because we may + have been value numbering optimistically, and + iterating. They may become non-constant in this case, + even if they were optimistically constant. */ + VN_INFO (lhs)->has_constants = false; + VN_INFO (lhs)->expr = NULL_TREE; + } + + if (TREE_CODE (lhs) == SSA_NAME + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) + changed = defs_to_varying (stmt); + /* ??? We should handle stores from calls. */ + else if (TREE_CODE (lhs) == SSA_NAME) + { + if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST)) + changed = visit_reference_op_call (lhs, stmt); + else + changed = defs_to_varying (stmt); + } + else + changed = defs_to_varying (stmt); + } + } + done: + return changed; +} + +/* Compare two operands by reverse postorder index */ + +static int +compare_ops (const void *pa, const void *pb) +{ + const tree opa = *((const tree *)pa); + const tree opb = *((const tree *)pb); + gimple opstmta = SSA_NAME_DEF_STMT (opa); + gimple opstmtb = SSA_NAME_DEF_STMT (opb); + basic_block bba; + basic_block bbb; + + if (gimple_nop_p (opstmta) && gimple_nop_p (opstmtb)) + return 0; + else if (gimple_nop_p (opstmta)) + return -1; + else if (gimple_nop_p (opstmtb)) + return 1; + + bba = gimple_bb (opstmta); + bbb = gimple_bb (opstmtb); + + if (!bba && !bbb) + return 0; + else if (!bba) + return -1; + else if (!bbb) + return 1; + + if (bba == bbb) + { + if (gimple_code (opstmta) == GIMPLE_PHI + && gimple_code (opstmtb) == GIMPLE_PHI) + return 0; + else if (gimple_code (opstmta) == GIMPLE_PHI) + return -1; + else if (gimple_code (opstmtb) == GIMPLE_PHI) + return 1; + return gimple_uid (opstmta) - gimple_uid (opstmtb); + } + return rpo_numbers[bba->index] - rpo_numbers[bbb->index]; +} + +/* Sort an array containing members of a strongly connected component + SCC so that the members are ordered by RPO number. + This means that when the sort is complete, iterating through the + array will give you the members in RPO order. */ + +static void +sort_scc (VEC (tree, heap) *scc) +{ + qsort (VEC_address (tree, scc), + VEC_length (tree, scc), + sizeof (tree), + compare_ops); +} + +/* Process a strongly connected component in the SSA graph. */ + +static void +process_scc (VEC (tree, heap) *scc) +{ + /* If the SCC has a single member, just visit it. */ + + if (VEC_length (tree, scc) == 1) + { + tree use = VEC_index (tree, scc, 0); + if (!VN_INFO (use)->use_processed) + visit_use (use); + } + else + { + tree var; + unsigned int i; + unsigned int iterations = 0; + bool changed = true; + + /* Iterate over the SCC with the optimistic table until it stops + changing. */ + current_info = optimistic_info; + while (changed) + { + changed = false; + iterations++; + /* As we are value-numbering optimistically we have to + clear the expression tables and the simplified expressions + in each iteration until we converge. */ + htab_empty (optimistic_info->nary); + htab_empty (optimistic_info->phis); + htab_empty (optimistic_info->references); + obstack_free (&optimistic_info->nary_obstack, NULL); + gcc_obstack_init (&optimistic_info->nary_obstack); + empty_alloc_pool (optimistic_info->phis_pool); + empty_alloc_pool (optimistic_info->references_pool); + for (i = 0; VEC_iterate (tree, scc, i, var); i++) + VN_INFO (var)->expr = NULL_TREE; + for (i = 0; VEC_iterate (tree, scc, i, var); i++) + changed |= visit_use (var); + } + + statistics_histogram_event (cfun, "SCC iterations", iterations); + + /* Finally, visit the SCC once using the valid table. */ + current_info = valid_info; + for (i = 0; VEC_iterate (tree, scc, i, var); i++) + visit_use (var); + } +} + +DEF_VEC_O(ssa_op_iter); +DEF_VEC_ALLOC_O(ssa_op_iter,heap); + +/* Pop the components of the found SCC for NAME off the SCC stack + and process them. Returns true if all went well, false if + we run into resource limits. */ + +static bool +extract_and_process_scc_for_name (tree name) +{ + VEC (tree, heap) *scc = NULL; + tree x; + + /* Found an SCC, pop the components off the SCC stack and + process them. */ + do + { + x = VEC_pop (tree, sccstack); + + VN_INFO (x)->on_sccstack = false; + VEC_safe_push (tree, heap, scc, x); + } while (x != name); + + /* Bail out of SCCVN in case a SCC turns out to be incredibly large. */ + if (VEC_length (tree, scc) + > (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE)) + { + if (dump_file) + fprintf (dump_file, "WARNING: Giving up with SCCVN due to " + "SCC size %u exceeding %u\n", VEC_length (tree, scc), + (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE)); + return false; + } + + if (VEC_length (tree, scc) > 1) + sort_scc (scc); + + if (dump_file && (dump_flags & TDF_DETAILS)) + print_scc (dump_file, scc); + + process_scc (scc); + + VEC_free (tree, heap, scc); + + return true; +} + +/* Depth first search on NAME to discover and process SCC's in the SSA + graph. + Execution of this algorithm relies on the fact that the SCC's are + popped off the stack in topological order. + Returns true if successful, false if we stopped processing SCC's due + to resource constraints. */ + +static bool +DFS (tree name) +{ + VEC(ssa_op_iter, heap) *itervec = NULL; + VEC(tree, heap) *namevec = NULL; + use_operand_p usep = NULL; + gimple defstmt; + tree use; + ssa_op_iter iter; + +start_over: + /* SCC info */ + VN_INFO (name)->dfsnum = next_dfs_num++; + VN_INFO (name)->visited = true; + VN_INFO (name)->low = VN_INFO (name)->dfsnum; + + VEC_safe_push (tree, heap, sccstack, name); + VN_INFO (name)->on_sccstack = true; + defstmt = SSA_NAME_DEF_STMT (name); + + /* Recursively DFS on our operands, looking for SCC's. */ + if (!gimple_nop_p (defstmt)) + { + /* Push a new iterator. */ + if (gimple_code (defstmt) == GIMPLE_PHI) + usep = op_iter_init_phiuse (&iter, defstmt, SSA_OP_ALL_USES); + else + usep = op_iter_init_use (&iter, defstmt, SSA_OP_ALL_USES); + } + else + clear_and_done_ssa_iter (&iter); + + while (1) + { + /* If we are done processing uses of a name, go up the stack + of iterators and process SCCs as we found them. */ + if (op_iter_done (&iter)) + { + /* See if we found an SCC. */ + if (VN_INFO (name)->low == VN_INFO (name)->dfsnum) + if (!extract_and_process_scc_for_name (name)) + { + VEC_free (tree, heap, namevec); + VEC_free (ssa_op_iter, heap, itervec); + return false; + } + + /* Check if we are done. */ + if (VEC_empty (tree, namevec)) + { + VEC_free (tree, heap, namevec); + VEC_free (ssa_op_iter, heap, itervec); + return true; + } + + /* Restore the last use walker and continue walking there. */ + use = name; + name = VEC_pop (tree, namevec); + memcpy (&iter, VEC_last (ssa_op_iter, itervec), + sizeof (ssa_op_iter)); + VEC_pop (ssa_op_iter, itervec); + goto continue_walking; + } + + use = USE_FROM_PTR (usep); + + /* Since we handle phi nodes, we will sometimes get + invariants in the use expression. */ + if (TREE_CODE (use) == SSA_NAME) + { + if (! (VN_INFO (use)->visited)) + { + /* Recurse by pushing the current use walking state on + the stack and starting over. */ + VEC_safe_push(ssa_op_iter, heap, itervec, &iter); + VEC_safe_push(tree, heap, namevec, name); + name = use; + goto start_over; + +continue_walking: + VN_INFO (name)->low = MIN (VN_INFO (name)->low, + VN_INFO (use)->low); + } + if (VN_INFO (use)->dfsnum < VN_INFO (name)->dfsnum + && VN_INFO (use)->on_sccstack) + { + VN_INFO (name)->low = MIN (VN_INFO (use)->dfsnum, + VN_INFO (name)->low); + } + } + + usep = op_iter_next_use (&iter); + } +} + +/* Allocate a value number table. */ + +static void +allocate_vn_table (vn_tables_t table) +{ + table->phis = htab_create (23, vn_phi_hash, vn_phi_eq, free_phi); + table->nary = htab_create (23, vn_nary_op_hash, vn_nary_op_eq, NULL); + table->references = htab_create (23, vn_reference_hash, vn_reference_eq, + free_reference); + + gcc_obstack_init (&table->nary_obstack); + table->phis_pool = create_alloc_pool ("VN phis", + sizeof (struct vn_phi_s), + 30); + table->references_pool = create_alloc_pool ("VN references", + sizeof (struct vn_reference_s), + 30); +} + +/* Free a value number table. */ + +static void +free_vn_table (vn_tables_t table) +{ + htab_delete (table->phis); + htab_delete (table->nary); + htab_delete (table->references); + obstack_free (&table->nary_obstack, NULL); + free_alloc_pool (table->phis_pool); + free_alloc_pool (table->references_pool); +} + +static void +init_scc_vn (void) +{ + size_t i; + int j; + int *rpo_numbers_temp; + + calculate_dominance_info (CDI_DOMINATORS); + sccstack = NULL; + constant_to_value_id = htab_create (23, vn_constant_hash, vn_constant_eq, + free); + + constant_value_ids = BITMAP_ALLOC (NULL); + + next_dfs_num = 1; + next_value_id = 1; + + vn_ssa_aux_table = VEC_alloc (vn_ssa_aux_t, heap, num_ssa_names + 1); + /* VEC_alloc doesn't actually grow it to the right size, it just + preallocates the space to do so. */ + VEC_safe_grow_cleared (vn_ssa_aux_t, heap, vn_ssa_aux_table, num_ssa_names + 1); + gcc_obstack_init (&vn_ssa_aux_obstack); + + shared_lookup_phiargs = NULL; + shared_lookup_vops = NULL; + shared_lookup_references = NULL; + rpo_numbers = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS); + rpo_numbers_temp = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS); + pre_and_rev_post_order_compute (NULL, rpo_numbers_temp, false); + + /* RPO numbers is an array of rpo ordering, rpo[i] = bb means that + the i'th block in RPO order is bb. We want to map bb's to RPO + numbers, so we need to rearrange this array. */ + for (j = 0; j < n_basic_blocks - NUM_FIXED_BLOCKS; j++) + rpo_numbers[rpo_numbers_temp[j]] = j; + + XDELETE (rpo_numbers_temp); + + VN_TOP = create_tmp_var_raw (void_type_node, "vn_top"); + + /* Create the VN_INFO structures, and initialize value numbers to + TOP. */ + for (i = 0; i < num_ssa_names; i++) + { + tree name = ssa_name (i); + if (name) + { + VN_INFO_GET (name)->valnum = VN_TOP; + VN_INFO (name)->expr = NULL_TREE; + VN_INFO (name)->value_id = 0; + } + } + + renumber_gimple_stmt_uids (); + + /* Create the valid and optimistic value numbering tables. */ + valid_info = XCNEW (struct vn_tables_s); + allocate_vn_table (valid_info); + optimistic_info = XCNEW (struct vn_tables_s); + allocate_vn_table (optimistic_info); +} + +void +free_scc_vn (void) +{ + size_t i; + + htab_delete (constant_to_value_id); + BITMAP_FREE (constant_value_ids); + VEC_free (tree, heap, shared_lookup_phiargs); + VEC_free (tree, gc, shared_lookup_vops); + VEC_free (vn_reference_op_s, heap, shared_lookup_references); + XDELETEVEC (rpo_numbers); + + for (i = 0; i < num_ssa_names; i++) + { + tree name = ssa_name (i); + if (name + && VN_INFO (name)->needs_insertion) + release_ssa_name (name); + } + obstack_free (&vn_ssa_aux_obstack, NULL); + VEC_free (vn_ssa_aux_t, heap, vn_ssa_aux_table); + + VEC_free (tree, heap, sccstack); + free_vn_table (valid_info); + XDELETE (valid_info); + free_vn_table (optimistic_info); + XDELETE (optimistic_info); +} + +/* Set the value ids in the valid hash tables. */ + +static void +set_hashtable_value_ids (void) +{ + htab_iterator hi; + vn_nary_op_t vno; + vn_reference_t vr; + vn_phi_t vp; + + /* Now set the value ids of the things we had put in the hash + table. */ + + FOR_EACH_HTAB_ELEMENT (valid_info->nary, + vno, vn_nary_op_t, hi) + { + if (vno->result) + { + if (TREE_CODE (vno->result) == SSA_NAME) + vno->value_id = VN_INFO (vno->result)->value_id; + else if (is_gimple_min_invariant (vno->result)) + vno->value_id = get_or_alloc_constant_value_id (vno->result); + } + } + + FOR_EACH_HTAB_ELEMENT (valid_info->phis, + vp, vn_phi_t, hi) + { + if (vp->result) + { + if (TREE_CODE (vp->result) == SSA_NAME) + vp->value_id = VN_INFO (vp->result)->value_id; + else if (is_gimple_min_invariant (vp->result)) + vp->value_id = get_or_alloc_constant_value_id (vp->result); + } + } + + FOR_EACH_HTAB_ELEMENT (valid_info->references, + vr, vn_reference_t, hi) + { + if (vr->result) + { + if (TREE_CODE (vr->result) == SSA_NAME) + vr->value_id = VN_INFO (vr->result)->value_id; + else if (is_gimple_min_invariant (vr->result)) + vr->value_id = get_or_alloc_constant_value_id (vr->result); + } + } +} + +/* Do SCCVN. Returns true if it finished, false if we bailed out + due to resource constraints. */ + +bool +run_scc_vn (bool may_insert_arg) +{ + size_t i; + tree param; + bool changed = true; + + may_insert = may_insert_arg; + + init_scc_vn (); + current_info = valid_info; + + for (param = DECL_ARGUMENTS (current_function_decl); + param; + param = TREE_CHAIN (param)) + { + if (gimple_default_def (cfun, param) != NULL) + { + tree def = gimple_default_def (cfun, param); + SSA_VAL (def) = def; + } + } + + for (i = 1; i < num_ssa_names; ++i) + { + tree name = ssa_name (i); + if (name + && VN_INFO (name)->visited == false + && !has_zero_uses (name)) + if (!DFS (name)) + { + free_scc_vn (); + may_insert = false; + return false; + } + } + + /* Initialize the value ids. */ + + for (i = 1; i < num_ssa_names; ++i) + { + tree name = ssa_name (i); + vn_ssa_aux_t info; + if (!name) + continue; + info = VN_INFO (name); + if (info->valnum == name) + info->value_id = get_next_value_id (); + else if (is_gimple_min_invariant (info->valnum)) + info->value_id = get_or_alloc_constant_value_id (info->valnum); + } + + /* Propagate until they stop changing. */ + while (changed) + { + changed = false; + for (i = 1; i < num_ssa_names; ++i) + { + tree name = ssa_name (i); + vn_ssa_aux_t info; + if (!name) + continue; + info = VN_INFO (name); + if (TREE_CODE (info->valnum) == SSA_NAME + && info->valnum != name + && info->value_id != VN_INFO (info->valnum)->value_id) + { + changed = true; + info->value_id = VN_INFO (info->valnum)->value_id; + } + } + } + + set_hashtable_value_ids (); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Value numbers:\n"); + for (i = 0; i < num_ssa_names; i++) + { + tree name = ssa_name (i); + if (name + && VN_INFO (name)->visited + && SSA_VAL (name) != name) + { + print_generic_expr (dump_file, name, 0); + fprintf (dump_file, " = "); + print_generic_expr (dump_file, SSA_VAL (name), 0); + fprintf (dump_file, "\n"); + } + } + } + + may_insert = false; + return true; +} + +/* Return the maximum value id we have ever seen. */ + +unsigned int +get_max_value_id (void) +{ + return next_value_id; +} + +/* Return the next unique value id. */ + +unsigned int +get_next_value_id (void) +{ + return next_value_id++; +} + + +/* Compare two expressions E1 and E2 and return true if they are equal. */ + +bool +expressions_equal_p (tree e1, tree e2) +{ + /* The obvious case. */ + if (e1 == e2) + return true; + + /* If only one of them is null, they cannot be equal. */ + if (!e1 || !e2) + return false; + + /* Recurse on elements of lists. */ + if (TREE_CODE (e1) == TREE_LIST && TREE_CODE (e2) == TREE_LIST) + { + tree lop1 = e1; + tree lop2 = e2; + for (lop1 = e1, lop2 = e2; + lop1 || lop2; + lop1 = TREE_CHAIN (lop1), lop2 = TREE_CHAIN (lop2)) + { + if (!lop1 || !lop2) + return false; + if (!expressions_equal_p (TREE_VALUE (lop1), TREE_VALUE (lop2))) + return false; + } + return true; + } + + /* Now perform the actual comparison. */ + if (TREE_CODE (e1) == TREE_CODE (e2) + && operand_equal_p (e1, e2, OEP_PURE_SAME)) + return true; + + return false; +} + +/* Sort the VUSE array so that we can do equality comparisons + quicker on two vuse vecs. */ + +void +sort_vuses (VEC (tree,gc) *vuses) +{ + if (VEC_length (tree, vuses) > 1) + qsort (VEC_address (tree, vuses), + VEC_length (tree, vuses), + sizeof (tree), + operand_build_cmp); +} + +/* Sort the VUSE array so that we can do equality comparisons + quicker on two vuse vecs. */ + +void +sort_vuses_heap (VEC (tree,heap) *vuses) +{ + if (VEC_length (tree, vuses) > 1) + qsort (VEC_address (tree, vuses), + VEC_length (tree, vuses), + sizeof (tree), + operand_build_cmp); +} + + +/* Return true if the nary operation NARY may trap. This is a copy + of stmt_could_throw_1_p adjusted to the SCCVN IL. */ + +bool +vn_nary_may_trap (vn_nary_op_t nary) +{ + tree type; + tree rhs2; + bool honor_nans = false; + bool honor_snans = false; + bool fp_operation = false; + bool honor_trapv = false; + bool handled, ret; + unsigned i; + + if (TREE_CODE_CLASS (nary->opcode) == tcc_comparison + || TREE_CODE_CLASS (nary->opcode) == tcc_unary + || TREE_CODE_CLASS (nary->opcode) == tcc_binary) + { + type = nary->type; + fp_operation = FLOAT_TYPE_P (type); + if (fp_operation) + { + honor_nans = flag_trapping_math && !flag_finite_math_only; + honor_snans = flag_signaling_nans != 0; + } + else if (INTEGRAL_TYPE_P (type) + && TYPE_OVERFLOW_TRAPS (type)) + honor_trapv = true; + } + rhs2 = nary->op[1]; + ret = operation_could_trap_helper_p (nary->opcode, fp_operation, + honor_trapv, + honor_nans, honor_snans, rhs2, + &handled); + if (handled + && ret) + return true; + + for (i = 0; i < nary->length; ++i) + if (tree_could_trap_p (nary->op[i])) + return true; + + return false; +}