... but you also mentioned strrchr, and there is a qemu bug there. The REV (predicate) instruction doesn't seem to be doing the right thing -- input 0x1 -> output 0x80000000 which is not correct for the current vector length (64).
** Changed in: qemu Status: Invalid => Confirmed -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1908551 Title: aarch64 SVE emulation breaks strnlen and strrchr Status in QEMU: Confirmed Bug description: arm optimized-routines have sve string functions with test code. the test worked up until recently: with qemu-5.2.0 i see $ qemu-aarch64 build/bin/test/strnlen PASS strnlen PASS __strnlen_aarch64 __strnlen_aarch64_sve (0x490fa0, 32) len 32 returned 64, expected 32 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80" __strnlen_aarch64_sve (0x490fa0, 32) len 33 returned 64, expected 32 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80a" __strnlen_aarch64_sve (0x490fa0, 33) len 33 returned 64, expected 33 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80a" __strnlen_aarch64_sve (0x490fa0, 32) len 34 returned 64, expected 32 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80ab" __strnlen_aarch64_sve (0x490fa0, 33) len 34 returned 64, expected 33 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80ab" __strnlen_aarch64_sve (0x490fa0, 34) len 34 returned 64, expected 34 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80ab" __strnlen_aarch64_sve (0x490fa0, 32) len 35 returned 64, expected 32 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80a\x00c" __strnlen_aarch64_sve (0x490fa0, 33) len 35 returned 64, expected 33 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80ab\x00" __strnlen_aarch64_sve (0x490fa0, 34) len 35 returned 64, expected 34 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80abc" __strnlen_aarch64_sve (0x490fa0, 35) len 35 returned 64, expected 35 input: "abcdefghijklmnopqrstuvwxyz\{|}~\x7f\x80abc" FAIL __strnlen_aarch64_sve however the test passes with qemu-aarch64 -cpu max,sve-max-vq=2 there should be nothing vector length specific in the code. i haven't debugged it further, to reproduce the issue clone https://github.com/ARM-software/optimized-routines and run 'make build/bin/test/strnlen' with a config.mk like SUBS = string ARCH = aarch64 CROSS_COMPILE = aarch64-none-linux-gnu- CC = $(CROSS_COMPILE)gcc CFLAGS = -std=c99 -pipe -O3 CFLAGS += -march=armv8.2-a+sve EMULATOR = qemu-aarch64 (native compilation works too, and you can run 'make check' to run all string tests) this will build a static linked executable into build/bin/test. if you want a smaller test case edit string/test/strnlen.c To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1908551/+subscriptions