https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100866
Bug ID: 100866
Summary: PPC: Inefficient code for vec_revb(vector unsigned
short) < P9
Product: gcc
Version: 8.3.1
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: ---
Input:
vector unsigned short revb(vector unsigned short a)
{
return vec_revb(a);
}
creates:
_Z4revbDv8_t:
.LFB1:
.cfi_startproc
.LCF1:
0: addis 2,12,.TOC.-.LCF1@ha
addi 2,2,.TOC.-.LCF1@l
.localentry _Z4revbDv8_t,.-_Z4revbDv8_t
addis 9,2,.LC1@toc@ha
addi 9,9,.LC1@toc@l
lvx 0,0,9
xxlnor 32,32,32
vperm 2,2,2,0
blr
Optimal code sequence:
vector unsigned short revb_pwr7(vector unsigned short a)
{
return vec_rl(a, vec_splats((unsigned short)8));
}
_Z9revb_pwr7Dv8_t:
.LFB2:
.cfi_startproc
.localentry _Z9revb_pwr7Dv8_t,1
vspltish 0,8
vrlh 2,2,0
blr
