https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115021
--- Comment #2 from Roger Sayle <roger at nextmovesoftware dot com> ---
Here's a reduced test case that should be unaffected by the pending changes to
how V8QI shifts are expanded. Note that the final "t -= t4" is required to
convince the register allocator to "spill".
typedef signed char v16qi __attribute__ ((__vector_size__ (16)));
// sign-extend low 3 bits to a byte.
v16qi foo (v16qi x) {
v16qi t7 = (v16qi){7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7};
v16qi t4 = (v16qi){4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4};
v16qi t = x & t7;
t ^= t4;
t -= t4;
return t;
}
which produces:
foo: movl $67372036, %eax
vmovdqa %xmm0, %xmm2
vpbroadcastd %eax, %xmm1
movl $117901063, %eax
vpbroadcastd %eax, %xmm3
vmovdqa %xmm1, %xmm0
vmovdqa %xmm3, -24(%rsp)
vmovdqa -24(%rsp), %xmm4
vpternlogd $120, %xmm2, %xmm4, %xmm0
vpsubb %xmm1, %xmm0, %xmm0
ret
