https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113431
--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to JuzheZhong from comment #11) > I think this following: > > https://godbolt.org/z/5sWEWWGox > > ARM SVE GCC-11 correctly vectorize this codes. > > But both GCC-12 and GCC-13 failed to vectorize it. > > GCC-14 vectorize it in a wrong way. > > Would it be possible to recover it back to GCC-11 ? With GCC 11 it probably SLP vectorizes the completely unrolled nest. That can be recovered with -fno-tree-loop-vectorize on trunk which on x86_64 produces main: .LFB0: .cfi_startproc movl a+4(%rip), %edx xorl %eax, %eax movl $2, b(%rip) testl %edx, %edx sete %al movd %eax, %xmm0 setne %al movzbl %al, %eax pshufd $0, %xmm0, %xmm0 movups %xmm0, a+4(%rip) movd %eax, %xmm1 movups %xmm0, a+20(%rip) pshufd $0, %xmm1, %xmm0 movups %xmm0, a+40(%rip) movups %xmm0, a+56(%rip) ret
