https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100260
Bug ID: 100260
Summary: DSE: join stores
Product: gcc
Version: tree-ssa
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: david.bolvansky at gmail dot com
Target Milestone: ---
#include <string.h>
struct pam {
void *p1;
void *p2;
#ifdef LONG
unsigned long size;
#else
unsigned int pad;
unsigned int size;
#endif
};
extern int use(struct pam *param);
unsigned int foo(void) {
struct pam s_pam;
memset(&s_pam, 0, sizeof(struct pam));
s_pam.size = 1;
return use(&s_pam);
}
INT
foo():
sub rsp, 40
pxor xmm0, xmm0
mov rdi, rsp
mov DWORD PTR [rsp+16], 0
mov DWORD PTR [rsp+20], 1
movaps XMMWORD PTR [rsp], xmm0
call use(pam*)
add rsp, 40
ret
LONG
foo():
sub rsp, 40
pxor xmm0, xmm0
mov rdi, rsp
movaps XMMWORD PTR [rsp], xmm0
mov QWORD PTR [rsp+16], 1
call use(pam*)
add rsp, 40
ret
Stores
mov DWORD PTR [rsp+16], 0
mov DWORD PTR [rsp+20], 1
can be replaced with one mov QWORD..
