https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87323
Bug ID: 87323
Summary: More complicated assembly for sode with custom copy
constructor
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: bugzi...@poradnik-webmastera.com
Target Milestone: ---
[code]
#include <stdint.h>
typedef int32_t VInt __attribute((vector_size(32)));
class V1
{
VInt v;
public:
constexpr V1(const V1& v) = default;
//constexpr V1(const V1& v) : v(v.v) {}
constexpr V1(const VInt& v) : v(v) {}
constexpr V1 operator+(const V1& v2) const
{ return V1(v + v2.v); }
constexpr V1 operator*(const V1& v2) const
{ return V1(v * v2.v); }
constexpr operator VInt() const
{ return v; }
};
V1 test1(V1 a, V1 b, V1 c)
{
return a * c + b * c;
}
[/code]
When code above is compiled, gcc produces following assembly:
[out]
test1(V1, V1, V1):
vpaddd ymm0, ymm1, ymm0
vpmulld ymm0, ymm0, ymm2
ret
[/out]
However when I comment out default copy constructor and uncomment custom one
(which should be equivalent), generated assembly is as follows:
[out]
test1(V1, V1, V1):
vmovdqa ymm0, YMMWORD PTR [rcx]
mov rax, rdi
vpmulld ymm1, ymm0, YMMWORD PTR [rsi]
vpmulld ymm0, ymm0, YMMWORD PTR [rdx]
vpaddd ymm0, ymm1, ymm0
vmovdqa YMMWORD PTR [rdi], ymm0
vzeroupper
ret
[/out]
