https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87870
Bug ID: 87870
Summary: ppc64le generates poor code when loading constants
into TImode vars
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: bergner at gcc dot gnu.org
Target Milestone: ---
bergner@pike:~/gcc/BUGS/PR87507$ cat bug.i
__int128
foo (void)
{
return 1;
}
bergner@pike:~/gcc/BUGS/PR87507$
/home/bergner/gcc/build/gcc-fsf-mainline-pr87507-base-debug/gcc/xgcc
-B/home/bergner/gcc/build/gcc-fsf-mainline-pr87507-base-debug/gcc -O2 -S bug.i
bergner@pike:~/gcc/BUGS/PR87507$ cat bug.s
foo:
.LCF0:
0: addis 2,12,.TOC.-.LCF0@ha
addi 2,2,.TOC.-.LCF0@l
addis 9,2,.LC0@toc@ha
addi 9,9,.LC0@toc@l
ld 3,0(9)
ld 4,8(9)
blr
If you compile with -mno-altivec, then we get the two li insn code you'd
expect. The problem is that vsx_mov<mode>_64 doesn't have support for loading
constants into gprs, whereas movti_ppc64 (which is used when not targeting a
cpu with a vector unit) does.
