[PowerPC] Avoid VSX FMA mutate when killed product reg = addend reg

[oota-llvm.git] / lib / Target / PowerPC / PPCInstrInfo.cpp

diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp
index ff2633eac3f874e2bfafcb3e84eb5a0519f33f82..daf8790fefcc5988e1c7d879f1f5bcf78af78beb 100644 (file)
--- a/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -1754,6 +1754,12 @@ protected:
 
         unsigned OldFMAReg = MI->getOperand(0).getReg();
 
+        // The transformation doesn't work well with things like:
+        //    %vreg5 = A-form-op %vreg5, %vreg11, %vreg5;
+        // so leave such things alone.
+        if (OldFMAReg == KilledProdReg)
+          continue;
+
         assert(OldFMAReg == AddendMI->getOperand(0).getReg() &&
                "Addend copy not tied to old FMA output!");