[llvm] [PowerPC] fix `ppc_fp128` `FABS` miscompile (PR #209286)

[Lei Huang via llvm-commits]

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@@ -383,6 +383,13 @@ entry:
 define ppc_fp128 @copysign_signmask(ppc_fp128 %x, i1 %s) {
 ; LE-LABEL: copysign_signmask:
 ; LE:       # %bb.0: # %entry
+; LE-NEXT:    fmr 0, 1
+; LE-NEXT:    xsabsdp 1, 1
+; LE-NEXT:    xscmpudp 0, 0, 1
+; LE-NEXT:    beq 0, .LBB6_2
+; LE-NEXT:  # %bb.1: # %entry
+; LE-NEXT:    xsnegdp 2, 2
+; LE-NEXT:  .LBB6_2: # %entry
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lei137 wrote:

why is that?  Shouldn't it be endian based?

https://github.com/llvm/llvm-project/pull/209286