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| author | Richard Biener <rguenther@suse.de> | 2022-07-21 13:20:47 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-07-21 13:20:47 +0200 |
| commit | 375668e0508fbe173af1ed519d8ae2b79f388d94 (patch) | |
| tree | f477d9a9880b00e974211c7beb58ff3fd1e73935 | |
| parent | dc477ffb4aba21e9cf47de22a4df6f2b23849505 (diff) | |
| download | gcc-375668e0508fbe173af1ed519d8ae2b79f388d94.zip gcc-375668e0508fbe173af1ed519d8ae2b79f388d94.tar.gz gcc-375668e0508fbe173af1ed519d8ae2b79f388d94.tar.bz2 | |
tree-optimization/106379 - add missing ~(a ^ b) folding for _Bool
The following makes sure to fold ~(a ^ b) to a == b for truth
values (but not vectors, we'd have to check for vector support of
equality). That turns the PR106379 testcase into a ranger one.
Note that while we arrive at ~(a ^ b) in a convoluted way from
original !a == !b one can eventually write the expression this
way directly as well.
PR tree-optimization/106379
* match.pd (~(a ^ b) -> a == b): New pattern.
* gcc.dg/pr106379-1.c: New testcase.
| -rw-r--r-- | gcc/match.pd | 6 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr106379-1.c | 9 |
2 files changed, 15 insertions, 0 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index 8bbc0db..88a1a5a 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1938,6 +1938,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (if (tree_nop_conversion_p (type, TREE_TYPE (@0))) (bit_not (bit_xor (view_convert @0) @1)))) +/* ~(a ^ b) is a == b for truth valued a and b. */ +(simplify + (bit_not (bit_xor:s truth_valued_p@0 truth_valued_p@1)) + (if (!VECTOR_TYPE_P (type)) + (convert (eq @0 @1)))) + /* (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x */ (simplify (bit_ior:c (bit_and:cs @0 (bit_not @2)) (bit_and:cs @1 @2)) diff --git a/gcc/testsuite/gcc.dg/pr106379-1.c b/gcc/testsuite/gcc.dg/pr106379-1.c new file mode 100644 index 0000000..7f2575e --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr106379-1.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-forwprop1" } */ + +_Bool foo (_Bool a, _Bool b) +{ + return !a == !b; +} + +/* { dg-final { scan-tree-dump "\[ab\]_\[0-9\]+\\(D\\) == \[ba\]_\[0-9\]+\\(D\\)" "forwprop1" } } */ |