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| author | Jakub Jelinek <jakub@redhat.com> | 2023-06-16 19:46:36 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2023-06-16 19:46:36 +0200 |
| commit | 5b67116a85298bbe358b036d34ad23119cebbdac (patch) | |
| tree | 34294066c2edc62d95a70004a97d274e27ba16b8 | |
| parent | ea1cd66f2200839d46a8b4dc140d18c00b849c82 (diff) | |
| download | gcc-5b67116a85298bbe358b036d34ad23119cebbdac.zip gcc-5b67116a85298bbe358b036d34ad23119cebbdac.tar.gz gcc-5b67116a85298bbe358b036d34ad23119cebbdac.tar.bz2 | |
tree-ssa-math-opts: Fix up uaddc/usubc pattern matching [PR110271]
The following testcase ICEs, because I misremembered what the return value
from match_arith_overflow is. It isn't true if __builtin_*_overflow was
matched, but it is true only in the BIT_NOT_EXPR case if stmt was removed.
So, if match_arith_overflow matches something, gsi_stmt (gsi) will not
be stmt and match_uaddc_usubc will be confused and can ICE.
The following patch fixes it by checking if gsi_stmt (gsi) == stmt,
in that case we know it is still a PLUS_EXPR/MINUS_EXPR and we can try to
pattern match it further as UADDC/USUBC.
2023-06-16 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/110271
* tree-ssa-math-opts.cc (math_opts_dom_walker::after_dom_children)
<case PLUS_EXPR>: Ignore return value from match_arith_overflow,
instead call match_uaddc_usubc only if gsi_stmt (gsi) is still stmt.
* gcc.c-torture/compile/pr110271.c: New test.
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/compile/pr110271.c | 24 | ||||
| -rw-r--r-- | gcc/tree-ssa-math-opts.cc | 9 |
2 files changed, 30 insertions, 3 deletions
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr110271.c b/gcc/testsuite/gcc.c-torture/compile/pr110271.c new file mode 100644 index 0000000..0cb91be --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/pr110271.c @@ -0,0 +1,24 @@ +/* PR tree-optimization/110271 */ + +unsigned a, b, c, d, e; + +void +foo (unsigned *x, int y, unsigned int *z) +{ + for (int i = 0; i < y; i++) + { + b += d; + a += b < d; + a += c = (__PTRDIFF_TYPE__) x > 3; + d = z[1] + (a < c); + a += e; + d += a < e; + } +} + +void +bar (unsigned int *z) +{ + unsigned *x = x; + foo (x, 9, z); +} diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc index b2764d4..d2b7129 100644 --- a/gcc/tree-ssa-math-opts.cc +++ b/gcc/tree-ssa-math-opts.cc @@ -5558,9 +5558,12 @@ math_opts_dom_walker::after_dom_children (basic_block bb) case PLUS_EXPR: case MINUS_EXPR: - if (!convert_plusminus_to_widen (&gsi, stmt, code) - && !match_arith_overflow (&gsi, stmt, code, m_cfg_changed_p)) - match_uaddc_usubc (&gsi, stmt, code); + if (!convert_plusminus_to_widen (&gsi, stmt, code)) + { + match_arith_overflow (&gsi, stmt, code, m_cfg_changed_p); + if (gsi_stmt (gsi) == stmt) + match_uaddc_usubc (&gsi, stmt, code); + } break; case BIT_NOT_EXPR: |