https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89028
Bug ID: 89028 Summary: 8-byte loop isn't vectorized Product: gcc Version: 9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: hjl.tools at gmail dot com Target Milestone: --- [hjl@gnu-skx-1 v64-2]$ cat y.i void rsqrt(char* restrict r, char* restrict a){ for (int i = 0; i < 8; i++){ r[i] += a[i]; } } [hjl@gnu-skx-1 v64-2]$ gcc -S -O2 y.i [hjl@gnu-skx-1 v64-2]$ cat y.s .file "y.i" .text .p2align 4,,15 .globl rsqrt .type rsqrt, @function rsqrt: .LFB0: .cfi_startproc xorl %eax, %eax .p2align 4,,10 .p2align 3 .L2: movzbl (%rsi,%rax), %edx addb %dl, (%rdi,%rax) addq $1, %rax cmpq $8, %rax jne .L2 ret .cfi_endproc .LFE0: .size rsqrt, .-rsqrt .ident "GCC: (GNU) 8.2.1 20190109 (Red Hat 8.2.1-7)" .section .note.GNU-stack,"",@progbits [hjl@gnu-skx-1 v64-2]$