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| author | Richard Biener <rguenther@suse.de> | 2023-03-03 10:41:29 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2023-03-03 12:06:49 +0100 |
| commit | 0132acc03cada2c3b47c48a205e821563153fc80 (patch) | |
| tree | 1af54b446514c41ab16f50bb93821fe4ccc23e5c /gcc | |
| parent | 59bc2b68de8041adf5eeb5bd18e5921f8a1f9567 (diff) | |
| download | gcc-0132acc03cada2c3b47c48a205e821563153fc80.zip gcc-0132acc03cada2c3b47c48a205e821563153fc80.tar.gz gcc-0132acc03cada2c3b47c48a205e821563153fc80.tar.bz2 | |
tree-optimization/109002 - partial PRE miscompilation
Partial PRE ends up miscompiling the testcase in PR109002, likely
involving a corner case when inifinite loops are involved. The
following avoids the miscompilation by addressing a long-standing
oddity that manifests in odd partial partial redundancies eliminated
that are full redundancies. The oddity is that while we properly
PHI translate the PA_IN set from the successors when computing
PA_OUT but we fail to do the same for ANTIC_IN which is supposed
to be unioned. That results in expressions with wrong virtual
operands being placed in the PA_OUT/IN sets and the pruning
machinery to go wrong because it assumes the expressions in the
sets have virtual operands that are valid in the respective blocks.
PR tree-optimization/109002
* tree-ssa-pre.cc (compute_partial_antic_aux): Properly
PHI-translate ANTIC_IN.
* gcc.dg/torture/pr109002.c: New testcase.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/testsuite/gcc.dg/torture/pr109002.c | 27 | ||||
| -rw-r--r-- | gcc/tree-ssa-pre.cc | 20 |
2 files changed, 41 insertions, 6 deletions
diff --git a/gcc/testsuite/gcc.dg/torture/pr109002.c b/gcc/testsuite/gcc.dg/torture/pr109002.c new file mode 100644 index 0000000..5575a4b --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr109002.c @@ -0,0 +1,27 @@ +/* { dg-do run } */ +/* { dg-additional-options "-ftree-pre -ftree-partial-pre" } */ + +extern void exit (int); + +int g; +int h; + +void __attribute__((noipa)) bar () +{ + if (g) + exit (0); +} + +int main(void) +{ + for (int i = 0; ; i++) { + for (int j = 0; j < g; j++); + if (i & 1) { + if (h) + continue; + if (g) + bar (); + g = 1; + } + } +} diff --git a/gcc/tree-ssa-pre.cc b/gcc/tree-ssa-pre.cc index f77732d..37cad36 100644 --- a/gcc/tree-ssa-pre.cc +++ b/gcc/tree-ssa-pre.cc @@ -2364,11 +2364,14 @@ compute_partial_antic_aux (basic_block block, unsigned int i; bitmap_iterator bi; - FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (e->dest), i, bi) - bitmap_value_insert_into_set (PA_OUT, - expression_for_id (i)); if (!gimple_seq_empty_p (phi_nodes (e->dest))) { + bitmap_set_t antic_in = bitmap_set_new (); + phi_translate_set (antic_in, ANTIC_IN (e->dest), e); + FOR_EACH_EXPR_ID_IN_SET (antic_in, i, bi) + bitmap_value_insert_into_set (PA_OUT, + expression_for_id (i)); + bitmap_set_free (antic_in); bitmap_set_t pa_in = bitmap_set_new (); phi_translate_set (pa_in, PA_IN (e->dest), e); FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi) @@ -2377,9 +2380,14 @@ compute_partial_antic_aux (basic_block block, bitmap_set_free (pa_in); } else - FOR_EACH_EXPR_ID_IN_SET (PA_IN (e->dest), i, bi) - bitmap_value_insert_into_set (PA_OUT, - expression_for_id (i)); + { + FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (e->dest), i, bi) + bitmap_value_insert_into_set (PA_OUT, + expression_for_id (i)); + FOR_EACH_EXPR_ID_IN_SET (PA_IN (e->dest), i, bi) + bitmap_value_insert_into_set (PA_OUT, + expression_for_id (i)); + } } } } |