diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2024-03-26 11:21:38 -1000 |
|---|---|---|
| committer | Michael Tokarev <mjt@tls.msk.ru> | 2024-03-31 22:14:59 +0300 |
| commit | 3cdfd68e4e6586c5c4583fb8cf6cc8074c73b51c (patch) | |
| tree | 1531c181b089260ec4904d76e8a5e284977e4e3f /tcg/optimize.c | |
| parent | d3e9e0fb29d35bb1a97cf348a99d82b29bae5d86 (diff) | |
tcg/optimize: Fix sign_mask for logical right-shift
The 'sign' computation is attempting to locate the sign bit that has
been repeated, so that we can test if that bit is known zero. That
computation can be zero if there are no known sign repetitions.
Cc: qemu-stable@nongnu.org
Fixes: 93a967fbb57 ("tcg/optimize: Propagate sign info for shifting")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2248
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
(cherry picked from commit 2911e9b95f3bb03783ae5ca3e2494dc3b44a9161)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Diffstat (limited to 'tcg/optimize.c')
| -rw-r--r-- | tcg/optimize.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tcg/optimize.c b/tcg/optimize.c index f2d01654c5..6fcdda68ef 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -2123,7 +2123,7 @@ static bool fold_shift(OptContext *ctx, TCGOp *op) * will not reduced the number of input sign repetitions. */ sign = (s_mask & -s_mask) >> 1; - if (!(z_mask & sign)) { + if (sign && !(z_mask & sign)) { ctx->s_mask = s_mask; } break; |