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| author | Richard Henderson <richard.henderson@linaro.org> | 2024-03-26 11:21:38 -1000 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2024-03-29 12:15:55 -1000 |
| commit | 2911e9b95f3bb03783ae5ca3e2494dc3b44a9161 (patch) | |
| tree | c316e248a8843ced44d250823663f6f3f337ae60 | |
| parent | 889cd5a8e2dd6cf8793faba22fda38b78553ae24 (diff) | |
| download | qemu-2911e9b95f3bb03783ae5ca3e2494dc3b44a9161.zip qemu-2911e9b95f3bb03783ae5ca3e2494dc3b44a9161.tar.gz qemu-2911e9b95f3bb03783ae5ca3e2494dc3b44a9161.tar.bz2 | |
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>
| -rw-r--r-- | tcg/optimize.c | 2 | ||||
| -rw-r--r-- | tests/tcg/aarch64/Makefile.target | 1 | ||||
| -rw-r--r-- | tests/tcg/aarch64/test-2248.c | 28 |
3 files changed, 30 insertions, 1 deletions
diff --git a/tcg/optimize.c b/tcg/optimize.c index 752cc5c..275db77 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -2376,7 +2376,7 @@ 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; diff --git a/tests/tcg/aarch64/Makefile.target b/tests/tcg/aarch64/Makefile.target index ea3e232..0efd565 100644 --- a/tests/tcg/aarch64/Makefile.target +++ b/tests/tcg/aarch64/Makefile.target @@ -10,6 +10,7 @@ VPATH += $(AARCH64_SRC) # Base architecture tests AARCH64_TESTS=fcvt pcalign-a64 lse2-fault +AARCH64_TESTS += test-2248 fcvt: LDFLAGS+=-lm diff --git a/tests/tcg/aarch64/test-2248.c b/tests/tcg/aarch64/test-2248.c new file mode 100644 index 0000000..aac2e17 --- /dev/null +++ b/tests/tcg/aarch64/test-2248.c @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* See https://gitlab.com/qemu-project/qemu/-/issues/2248 */ + +#include <assert.h> + +__attribute__((noinline)) +long test(long x, long y, long sh) +{ + long r; + asm("cmp %1, %2\n\t" + "cset x12, lt\n\t" + "and w11, w12, #0xff\n\t" + "cmp w11, #0\n\t" + "csetm x14, ne\n\t" + "lsr x13, x14, %3\n\t" + "sxtb %0, w13" + : "=r"(r) + : "r"(x), "r"(y), "r"(sh) + : "x11", "x12", "x13", "x14"); + return r; +} + +int main() +{ + long r = test(0, 1, 2); + assert(r == -1); + return 0; +} |