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| author | Andrew Pinski <quic_apinski@quicinc.com> | 2024-05-20 00:16:40 -0700 |
|---|---|---|
| committer | Andrew Pinski <quic_apinski@quicinc.com> | 2024-05-21 07:24:36 -0700 |
| commit | 49c87d22535ac4f8aacf088b3f462861c26cacb4 (patch) | |
| tree | 507f030e4aced5f9f608c86b7d5b87d3e6121085 /gcc/match.pd | |
| parent | 232a86f9640cde6908d0875b8df52c36030c5b5e (diff) | |
| download | gcc-49c87d22535ac4f8aacf088b3f462861c26cacb4.zip gcc-49c87d22535ac4f8aacf088b3f462861c26cacb4.tar.gz gcc-49c87d22535ac4f8aacf088b3f462861c26cacb4.tar.bz2 | |
match: Disable `(type)zero_one_valuep*CST` for 1bit signed types [PR115154]
The problem here is the pattern added in r13-1162-g9991d84d2a8435
assumes that it is well defined to multiply zero_one_valuep by the truncated
converted integer constant. It is well defined for all types except for signed 1bit types.
Where `a * -1` is produced which is undefined/
So disable this pattern for 1bit signed types.
Note the pattern added in r14-3432-gddd64a6ec3b38e is able to workaround the undefinedness except when
`-fsanitize=undefined` is turned on, this is why I added a testcase for that.
Bootstrapped and tested on x86_64-linux-gnu with no regressions.
PR tree-optimization/115154
gcc/ChangeLog:
* match.pd (convert (mult zero_one_valued_p@1 INTEGER_CST@2)): Disable
for 1bit signed types.
gcc/testsuite/ChangeLog:
* c-c++-common/ubsan/signed1bitfield-1.c: New test.
* gcc.c-torture/execute/signed1bitfield-1.c: New test.
Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
Diffstat (limited to 'gcc/match.pd')
| -rw-r--r-- | gcc/match.pd | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index 0f9c34f..35e3d82 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -2395,12 +2395,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (mult (convert @0) @1))) /* Narrow integer multiplication by a zero_one_valued_p operand. - Multiplication by [0,1] is guaranteed not to overflow. */ + Multiplication by [0,1] is guaranteed not to overflow except for + 1bit signed types. */ (simplify (convert (mult@0 zero_one_valued_p@1 INTEGER_CST@2)) (if (INTEGRAL_TYPE_P (type) && INTEGRAL_TYPE_P (TREE_TYPE (@0)) - && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@0))) + && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@0)) + && (TYPE_UNSIGNED (type) || TYPE_PRECISION (type) > 1)) (mult (convert @1) (convert @2)))) /* (X << C) != 0 can be simplified to X, when C is zero_one_valued_p. |