https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121649
Bug ID: 121649
Summary: [16 Regression] wrong code with _BitInt() conversions
(?) at -O2
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: zsojka at seznam dot cz
Target Milestone: ---
Host: x86_64-pc-linux-gnu
Target: aarch64-unknown-linux-gnu
Created attachment 62183
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62183&action=edit
reduced testcase
foo0() basically just returns the argument sb3, but removing the unused
arguments fixes the failure.
-fwrapv might not be needed, but I better keep it there to have defined signed
overflow.
Output:
$ aarch64-unknown-linux-gnu-gcc -O2 -fwrapv testcase.c -static
$ qemu-aarch64 -- ./a.out
qemu: uncaught target signal 6 (Aborted) - core dumped
Aborted
Value of 'x' is 0.
$ aarch64-unknown-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-aarch64//bin/aarch64-unknown-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-20250822141858-r16-3343-g62beefc4750fc1-checking-yes-rtl-df-extra-aarch64/bin/../libexec/gcc/aarch64-unknown-linux-gnu/16.0.0/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--enable-libsanitizer --with-sysroot=/usr/aarch64-unknown-linux-gnu
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=aarch64-unknown-linux-gnu
--with-ld=/usr/bin/aarch64-unknown-linux-gnu-ld
--with-as=/usr/bin/aarch64-unknown-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-20250822141858-r16-3343-g62beefc4750fc1-checking-yes-rtl-df-extra-aarch64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 16.0.0 20250822 (experimental) (GCC)
