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tree-ssa-copy.c (copy_prop_visit_assignment): Clean up by folding a COND_EXPR_COND in a nondestructive manner.

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* tree-ssa-copy.c (copy_prop_visit_assignment): Clean up by
	folding a COND_EXPR_COND in a nondestructive manner.

From-SVN: r99782
This commit is contained in:
Kazu Hirata 2005-05-16 18:10:20 +00:00 committed by Kazu Hirata
parent fe2d45c77f
commit 691aed8cce
2 changed files with 22 additions and 33 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2005-05-16 Kazu Hirata <kazu@cs.umass.edu>
* tree-ssa-copy.c (copy_prop_visit_assignment): Clean up by
folding a COND_EXPR_COND in a nondestructive manner.
2005-05-16 Fariborz Jahanian <fjahanian@apple.com>
* config/rs6000/altivec.md (altivec_vmrghb, altivec_vmrghh,

50
gcc/tree-ssa-copy.c
View File

@ -594,32 +594,18 @@ copy_prop_visit_cond_stmt (tree stmt, edge *taken_edge_p)
{
enum ssa_prop_result retval;
tree cond;
use_operand_p use_p;
ssa_op_iter iter;
unsigned num;
cond = COND_EXPR_COND (stmt);
retval = SSA_PROP_VARYING;
num = NUM_SSA_OPERANDS (stmt, SSA_OP_USE);
/* The only conditionals that we may be able to compute statically
are predicates involving at least one SSA_NAME. */
are predicates involving two SSA_NAMEs. */
if (COMPARISON_CLASS_P (cond)
&& num >= 1)
&& TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
&& TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME)
{
unsigned i;
tree *orig;
/* Save the original operands. */
orig = xmalloc (sizeof (tree) * num);
i = 0;
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
{
tree use = USE_FROM_PTR (use_p);
orig[i++] = use;
SET_USE (use_p, get_last_copy_of (use));
}
tree op0 = get_last_copy_of (TREE_OPERAND (cond, 0));
tree op1 = get_last_copy_of (TREE_OPERAND (cond, 1));
/* See if we can determine the predicate's value. */
if (dump_file && (dump_flags & TDF_DETAILS))
@ -629,22 +615,20 @@ copy_prop_visit_cond_stmt (tree stmt, edge *taken_edge_p)
print_generic_stmt (dump_file, cond, 0);
}
/* We can fold COND only and get a useful result only when we
have the same SSA_NAME on both sides of a comparison
operator. */
if (TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
&& TREE_OPERAND (cond, 0) == TREE_OPERAND (cond, 1))
/* We can fold COND and get a useful result only when we have
the same SSA_NAME on both sides of a comparison operator. */
if (op0 == op1)
{
*taken_edge_p = find_taken_edge (bb_for_stmt (stmt), fold (cond));
if (*taken_edge_p)
retval = SSA_PROP_INTERESTING;
tree folded_cond = fold_binary (TREE_CODE (cond), boolean_type_node,
op0, op1);
if (folded_cond)
{
basic_block bb = bb_for_stmt (stmt);
*taken_edge_p = find_taken_edge (bb, folded_cond);
if (*taken_edge_p)
retval = SSA_PROP_INTERESTING;
}
}
/* Restore the original operands. */
i = 0;
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
SET_USE (use_p, orig[i++]);
free (orig);
}
if (dump_file && (dump_flags & TDF_DETAILS) && *taken_edge_p)