https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101169
Kewen Lin <linkw at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |linkw at gcc dot gnu.org
Component|testsuite |rtl-optimization
--- Comment #4 from Kewen Lin <linkw at gcc dot gnu.org> ---
The culprit change did cause some code gen regression, take a function
testbc_var from fold-vec-extract-char.p7.c as example:
// compiled with -O2 -mcpu=power7
#include <altivec.h>
unsigned char
testbc_var (vector bool char vbc2, signed int si)
{
return vec_extract (vbc2, si);
}
on both Linux and aix 64-bit, or aix 32-bit, it generates one more addi than
before:
sub-optimal:
.L.testbc_var:
li 9,48
addi 10,1,-64
stxvw4x 34,10,9
rldicl 5,5,0,60
addi 9,5,-64 // these two insns
add 5,9,1 // can be optimized (see below)
lbz 3,48(5)
blr
vs. the previous:
.L.testbc_var:
addi 10,1,-64
li 9,48
stxvw4x 34,10,9
rldicl 5,5,0,60
add 5,10,5
lbz 3,48(5)
blr
