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| author | Richard Guenther <rguenther@suse.de> | 2005-08-01 08:52:59 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2005-08-01 08:52:59 +0000 |
| commit | ac264fef2367c4773f4ed4868bdaa13c39b1ab44 (patch) | |
| tree | 6c454da7c03895efb5f70d5099fddba16413ef4a | |
| parent | 19734dd84e999ade0e315247f0de9e1b176257bb (diff) | |
| download | gcc-ac264fef2367c4773f4ed4868bdaa13c39b1ab44.zip gcc-ac264fef2367c4773f4ed4868bdaa13c39b1ab44.tar.gz gcc-ac264fef2367c4773f4ed4868bdaa13c39b1ab44.tar.bz2 | |
re PR tree-optimization/23109 (compiler generates wrong code leading to spurious division by zero with -funsafe-math-optimizations (instead of -ftrapping-math))
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
| -rw-r--r-- | gcc/ChangeLog | 11 | ||||
| -rw-r--r-- | gcc/tree-ssa-loop-im.c | 1 | ||||
| -rw-r--r-- | gcc/tree-ssa-math-opts.c | 23 |
3 files changed, 30 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 1f090f4..07b3141 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -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, diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c index e3476c6..9281079 100644 --- a/gcc/tree-ssa-loop-im.c +++ b/gcc/tree-ssa-loop-im.c @@ -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, diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c index 9544a6c..bff3c1d 100644 --- a/gcc/tree-ssa-math-opts.c +++ b/gcc/tree-ssa-math-opts.c @@ -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 = |