https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113431
Bug ID: 113431
Summary: [14] RISC-V rv64gcv vector: Runtime mismatch at -O3
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: patrick at rivosinc dot com
Target Milestone: ---
Testcase:
int a[2][9];
int b;
int c;
int d;
int main() {
for (b = 0;b < 2; b++)
for (long e = 8; e > 0; e--)
a[b][e] = a[0][1] == 0;
if (!a[1][1])
return 0;
else
return 1;
}
Commands:
> /scratch/tc-testing/tc-jan-16-trunk/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O3 -march=rv64gcv red_copy.c -o user-config.out
> QEMU_CPU=rv64,vlen=128,v=true,vext_spec=v1.0,Zve32f=true,Zve64f=true timeout
> --verbose -k 0.1 1
> /scratch/tc-testing/tc-jan-16-trunk/build-rv64gcv/bin/qemu-riscv64
> user-config.out
> echo $?
1
> /scratch/tc-testing/tc-jan-16-trunk/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O2 -march=rv64gcv red_copy.c -o user-config.out
> QEMU_CPU=rv64,vlen=128,v=true,vext_spec=v1.0,Zve32f=true,Zve64f=true timeout
> --verbose -k 0.1 1
> /scratch/tc-testing/tc-jan-16-trunk/build-rv64gcv/bin/qemu-riscv64
> user-config.out
> echo $?
0
> /scratch/tc-testing/tc-jan-16-trunk/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O3 -march=rv64gc red_copy.c -o user-config.out
> QEMU_CPU=rv64,vlen=128,v=true,vext_spec=v1.0,Zve32f=true,Zve64f=true timeout
> --verbose -k 0.1 1
> /scratch/tc-testing/tc-jan-16-trunk/build-rv64gcv/bin/qemu-riscv64
> user-config.out
> echo $?
0
When a[1][1] is set a[0][1] is true(1) so a[1][1] == 0 should be false(0). At
-O3 rv64gcv the condition is evaluated incorrectly.
Godbolt: https://godbolt.org/z/Tfz3d646e
