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| author | Jakub Jelinek <jakub@redhat.com> | 2020-01-07 11:05:14 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2020-01-07 11:05:14 +0100 |
| commit | fb862fdfb53ecb189f8bd74b66de573a78045916 (patch) | |
| tree | 733c1ab99c29a45d7184f0131b1ae75029058b62 /gcc/tree-ssa-ccp.c | |
| parent | f26916c2acdda19e36e57fff97b296897ebcba76 (diff) | |
| download | gcc-fb862fdfb53ecb189f8bd74b66de573a78045916.zip gcc-fb862fdfb53ecb189f8bd74b66de573a78045916.tar.gz gcc-fb862fdfb53ecb189f8bd74b66de573a78045916.tar.bz2 | |
re PR tree-optimization/93156 (abused nonnull attribute evokes new segfault in gcc 10 since Nov 4 commit, 0fb958ab8aa)
PR tree-optimization/93156
* tree-ssa-ccp.c (bit_value_binop): For x * x note that the second
least significant bit is always clear.
* gcc.dg/tree-ssa/pr93156.c: New test.
From-SVN: r279951
Diffstat (limited to 'gcc/tree-ssa-ccp.c')
| -rw-r--r-- | gcc/tree-ssa-ccp.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c index add3d3f..be6647d 100644 --- a/gcc/tree-ssa-ccp.c +++ b/gcc/tree-ssa-ccp.c @@ -1650,6 +1650,17 @@ bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) TYPE_SIGN (TREE_TYPE (rhs2)), TYPE_PRECISION (TREE_TYPE (rhs2)), value_to_wide_int (r2val), r2val.mask); + /* (x * x) & 2 == 0. */ + if (code == MULT_EXPR && rhs1 == rhs2 && TYPE_PRECISION (type) > 1) + { + widest_int m = 2; + if (wi::sext (mask, TYPE_PRECISION (type)) != -1) + value = wi::bit_and_not (value, m); + else + value = 0; + mask = wi::bit_and_not (mask, m); + } + if (wi::sext (mask, TYPE_PRECISION (type)) != -1) { val.lattice_val = CONSTANT; |