https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87105
--- Comment #6 from Petr <kobalicek.petr at gmail dot com> ---
I think the test-case can even be simplified to something like this:
#include <algorithm>
#include <cmath>
struct Point {
double x, y;
void reset(double x, double y) {
this->x = x;
this->y = y;
}
};
void f1(Point* p, Point* a) {
p->reset(std::max(std::sqrt(p->x), a->x),
std::max(std::sqrt(p->y), a->y));
}
GCC is unable to vectorize it:
[-std=c++17 -O3 -mavx2 -fno-math-errno]
f1(Point*, Point*):
vsqrtsd xmm0, xmm0, QWORD PTR [rdi+8]
vmovsd xmm1, QWORD PTR [rsi+8]
vsqrtsd xmm2, xmm2, QWORD PTR [rdi]
vmaxsd xmm1, xmm1, xmm0
vmovsd xmm0, QWORD PTR [rsi]
vmaxsd xmm0, xmm0, xmm2
vunpcklpd xmm0, xmm0, xmm1
vmovups XMMWORD PTR [rdi], xmm0
ret
whereas clang can:
[-std=c++17 -O3 -mavx2 -fno-math-errno]
f1(Point*, Point*):
vsqrtpd xmm0, xmmword ptr [rdi]
vmovupd xmm1, xmmword ptr [rsi]
vmaxpd xmm0, xmm1, xmm0
vmovupd xmmword ptr [rdi], xmm0
ret
I think this is a much simpler test-case to start with.
