https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116972
Bug ID: 116972
Summary: missed vectorization when an array of type 'long' is
initialized to 0
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: 652023330028 at smail dot nju.edu.cn
Target Milestone: ---
Hello, we noticed that there seems to be a missing vectorization for the code
below. When 'arr' is of type 'int', it works as expected.
https://godbolt.org/z/drGx7WqP6
long arr [20];
void f() {
for (int i = 0; i < 20; i += 1)
{
arr [i] = 0;
}
}
GCC -O3:
f():
mov ecx, 20
xor eax, eax
mov edi, OFFSET FLAT:arr
rep stosq
ret
Expected code (Clang):
f():
xorps xmm0, xmm0
movaps xmmword ptr [rip + arr+144], xmm0
movaps xmmword ptr [rip + arr+128], xmm0
movaps xmmword ptr [rip + arr+112], xmm0
movaps xmmword ptr [rip + arr+96], xmm0
movaps xmmword ptr [rip + arr+80], xmm0
movaps xmmword ptr [rip + arr+64], xmm0
movaps xmmword ptr [rip + arr+48], xmm0
movaps xmmword ptr [rip + arr+32], xmm0
movaps xmmword ptr [rip + arr+16], xmm0
movaps xmmword ptr [rip + arr], xmm0
ret
Thank you very much for your time and effort! We look forward to hearing from
you.
