https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43147
--- Comment #15 from Hongtao.liu <crazylht at gmail dot com> ---
> I think pass_combine should be extended to force illegitimate constant
> to constant pool and recog load insn again, It looks like a general
> optimization that better not do it in the backend.
The issue can also be solved by folding __builtin_ia32_shufps to gimple
VEC_PERM_EXPR, .i.e the below testcase doesn't have the problem
typedef int v4si __attribute__((vector_size (16)));
v4si
foo ()
{
v4si a = __extension__ (v4si) {4, 3, 2, 1};
v4si b = __extension__ (v4si) {5, 6, 7, 8};
v4si c = __builtin_shufflevector (a, b, 1, 4, 2, 7);
v4si d = __builtin_shuffle (c, __extension__ (v4si) { 3, 2, 0, 1 });
return d;
}
foo():
movdqa .LC0(%rip), %xmm0
ret
.LC0:
.long 8
.long 2
.long 3
.long 5
