https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96481
Bug ID: 96481
Summary: SLP fail to vectorize VEC_COND_EXPR pattern.
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: crazylht at gmail dot com
Target Milestone: ---
testcase not vectorized:
-----
#include <x86intrin.h>
inline unsigned opt(unsigned a, unsigned b, unsigned c, unsigned d) {
return a > b ? c : d;
}
void opt( unsigned * __restrict dst, const unsigned *pa, const unsigned *pb,
const unsigned *pc, const unsigned *pd )
{
*dst++ = opt(*pa++, *pb++, *pc++, *pd++);
*dst++ = opt(*pa++, *pb++, *pc++, *pd++);
*dst++ = opt(*pa++, *pb++, *pc++, *pd++);
*dst++ = opt(*pa++, *pb++, *pc++, *pd++);
}
----
testcase successfully vectorized:
----
inline unsigned opt(unsigned a, unsigned b, unsigned c, unsigned d) {
return a > b ? c : d;
}
void opt( unsigned * __restrict dst, const unsigned *pa, const unsigned *pb,
const unsigned *pc, const unsigned *pd )
{
for (int i = 0; i != 4; i++)
*dst++ = opt(*pa++, *pb++, *pc++, *pd++);
}
----
llvm can handle both case
refer to https://godbolt.org/z/jYoPxT
