From 162c54b7c1982d3a4b53c51d016c8adb941494fc Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 26 Mar 2024 11:21:38 -1000 Subject: [PATCH] tcg/optimize: Fix sign_mask for logical right-shift MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Philippe Mathieu-Daudé (cherry picked from commit 2911e9b95f3bb03783ae5ca3e2494dc3b44a9161) Signed-off-by: Michael Tokarev (Mjt: trivial context fixup in tests/tcg/aarch64/Makefile.target) --- tcg/optimize.c | 2 +- tests/tcg/aarch64/Makefile.target | 1 + tests/tcg/aarch64/test-2248.c | 28 ++++++++++++++++++++++++++++ 3 files changed, 30 insertions(+), 1 deletion(-) create mode 100644 tests/tcg/aarch64/test-2248.c diff --git a/tcg/optimize.c b/tcg/optimize.c index ae081ab29c0..b6f6436c74c 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -1907,7 +1907,7 @@ 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 5e4ea7c998f..474f61bc301 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 +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 00000000000..aac2e178368 --- /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 + +__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; +} -- 2.39.5