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re PR tree-optimization/23109 (compiler generates wrong code leading to spurious division by zero with -funsafe-math-optimizations (instead of -ftrapping-math))

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2005-08-01  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/23109
	* tree-ssa-math-opts.c (execute_cse_reciprocals_1):
	If trapping math is in effect, use post-dominator information
	to check if we'd in any case reach a trapping point before
	doing the reciprocal insertion.
	(execute_cse_reciprocals): Compute post-dominators, if necessary.
	* tree-ssa-loop-im.c (determine_invariantness_stmt): RDIV
	expressions are invariant only if trapping math is not in effect.

From-SVN: r102627
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Richard Guenther 2005-08-01 08:52:59 +00:00 committed by Richard Biener
parent 19734dd84e
commit ac264fef23
3 changed files with 30 additions and 5 deletions
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11
gcc/ChangeLog
View File

@ -1,3 +1,14 @@
2005-08-01 Richard Guenther <rguenther@suse.de>
PR tree-optimization/23109
* tree-ssa-math-opts.c (execute_cse_reciprocals_1):
If trapping math is in effect, use post-dominator information
to check if we'd in any case reach a trapping point before
doing the reciprocal insertion.
(execute_cse_reciprocals): Compute post-dominators, if necessary.
* tree-ssa-loop-im.c (determine_invariantness_stmt): RDIV
expressions are invariant only if trapping math is not in effect.
2005-08-01 Razya Ladelsky <razya@il.ibm.com>
* cgraph.h (update_call_expr, cgraph_copy_node_for_versioning,

1
gcc/tree-ssa-loop-im.c
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@ -610,6 +610,7 @@ determine_invariantness_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED,
&& (rhs = TREE_OPERAND (stmt, 1)) != NULL
&& TREE_CODE (rhs) == RDIV_EXPR
&& flag_unsafe_math_optimizations
&& !flag_trapping_math
&& outermost_invariant_loop_expr (TREE_OPERAND (rhs, 1),
loop_containing_stmt (stmt)) != NULL
&& outermost_invariant_loop_expr (rhs,

23
gcc/tree-ssa-math-opts.c
View File

@ -69,6 +69,7 @@ execute_cse_reciprocals_1 (block_stmt_iterator *bsi, tree def, bool phi)
imm_use_iterator use_iter;
tree t, new_stmt, type;
int count = 0;
bool ok = !flag_trapping_math;
/* Find uses. */
FOR_EACH_IMM_USE_FAST (use_p, use_iter, def)
@ -77,13 +78,18 @@ execute_cse_reciprocals_1 (block_stmt_iterator *bsi, tree def, bool phi)
if (TREE_CODE (use_stmt) == MODIFY_EXPR
&& TREE_CODE (TREE_OPERAND (use_stmt, 1)) == RDIV_EXPR
&& TREE_OPERAND (TREE_OPERAND (use_stmt, 1), 1) == def)
{
if (++count == 2)
break;
}
{
++count;
/* Check if this use post-dominates the insertion point. */
if (ok || dominated_by_p (CDI_POST_DOMINATORS, bsi->bb,
bb_for_stmt (use_stmt)))
ok = true;
}
if (count >= 2 && ok)
break;
}
if (count < 2)
if (count < 2 || !ok)
return;
/* Make a variable with the replacement and substitute it. */
@ -116,6 +122,10 @@ static void
execute_cse_reciprocals (void)
{
basic_block bb;
if (flag_trapping_math)
calculate_dominance_info (CDI_POST_DOMINATORS);
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
@ -143,6 +153,9 @@ execute_cse_reciprocals (void)
execute_cse_reciprocals_1 (&bsi, def, false);
}
}
if (flag_trapping_math)
free_dominance_info (CDI_POST_DOMINATORS);
}
struct tree_opt_pass pass_cse_reciprocals =