On 26/3/24 23:22, Richard Henderson wrote:
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: [email protected]
Fixes: 93a967fbb57 ("tcg/optimize: Propagate sign info for shifting")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2248
Signed-off-by: Richard Henderson <[email protected]>
---
tcg/optimize.c | 2 +-
tests/tcg/aarch64/test-2248.c | 25 +++++++++++++++++++++++++
tests/tcg/aarch64/Makefile.target | 1 +
3 files changed, 27 insertions(+), 1 deletion(-)
create mode 100644 tests/tcg/aarch64/test-2248.c
diff --git a/tests/tcg/aarch64/test-2248.c b/tests/tcg/aarch64/test-2248.c
new file mode 100644
index 0000000000..6cc20e3c6c
--- /dev/null
+++ b/tests/tcg/aarch64/test-2248.c
@@ -0,0 +1,25 @@
/* 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;
+}
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
