https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106770
Bug ID: 106770
Summary: PPCLE: Unnecessary xxpermdi before mfvsrd
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jens.seifert at de dot ibm.com
Target Milestone: ---
#include <altivec.h>
int cmp2(double a, double b)
{
vector double va = vec_promote(a, 1);
vector double vb = vec_promote(b, 1);
vector long long vlt = (vector long long)vec_cmplt(va, vb);
vector long long vgt = (vector long long)vec_cmplt(vb, va);
vector signed long long vr = vec_sub(vlt, vgt);
return vec_extract(vr, 1);
}
Generates:
_Z4cmp2dd:
.LFB1:
.cfi_startproc
xxpermdi 1,1,1,0
xxpermdi 2,2,2,0
xvcmpgtdp 33,2,1
xvcmpgtdp 32,1,2
vsubudm 0,1,0
xxpermdi 0,32,32,3
mfvsrd 3,0
extsw 3,3
blr
The unnecessary xxpermdi for vec_promote are already reported in another
bugzilla case.
mfvsrd can access all 64 vector registers directly and xxpermdi is not
required.
mfvsrd 3,32 expected instead xxpermdi 0,32,32,3 + mfvsrd 3,0
