From 3cdfd68e4e6586c5c4583fb8cf6cc8074c73b51c 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 --- 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 f2d01654c59..6fcdda68ef4 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; diff --git a/tests/tcg/aarch64/Makefile.target b/tests/tcg/aarch64/Makefile.target index ea3e232e65f..0efd565f05e 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 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