[Bug target/100996] New: rs6000 p10 vector add-add fusion should work with -m32 but doesn't

[acsawdey at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100996

            Bug ID: 100996
           Summary: rs6000 p10 vector add-add fusion should work with -m32
                    but doesn't
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: acsawdey at gcc dot gnu.org
  Target Milestone: ---

The fusion-p10-addadd.c test case does not get vector add-add fusion when
compiling with -m32:

/home/sawdey/work/gcc/trunk/build/gcc/xgcc
-B/home/sawdey/work/gcc/trunk/build/gcc/
/home/sawdey/work/gcc/trunk/gcc/gcc/testsuite/gcc.target/powerpc/fusion-p10-addadd.c
 -m32  -fdiagnostics-plain-output  -mcpu=power10 -O3 -dap -fno-ident -S

typedef vector long vlong;
vlong vaddadd(vlong a, vlong b, vlong c)
{
  return a+b+c;
}

vaddadd:
.LFB3:
        .cfi_startproc
        vadduwm 2,2,3    # 8    [c=4 l=4]  addv4si3
        vadduwm 2,2,4    # 14   [c=4 l=4]  addv4si3
        blr              # 24   [c=4 l=4]  simple_return
        .cfi_endproc