diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 3e549d942823..8afd2f8d0044 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2769,6 +2769,10 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
         if (!RHSF)
           break;
 
+        // We can't convert a PPC double double.
+        if (RHSF->getType()->isPPC_FP128Ty())
+          break;
+
         const fltSemantics *Sem;
         // FIXME: This shouldn't be here.
         if (LHSExt->getSrcTy()->isFloatTy())
@@ -2779,8 +2783,6 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
           Sem = &APFloat::IEEEquad;
         else if (LHSExt->getSrcTy()->isX86_FP80Ty())
           Sem = &APFloat::x87DoubleExtended;
-        else if (LHSExt->getSrcTy()->isPPC_FP128Ty())
-          Sem = &APFloat::PPCDoubleDouble;
         else
           break;
 
diff --git a/llvm/test/Transforms/InstCombine/fcmp.ll b/llvm/test/Transforms/InstCombine/fcmp.ll
index b41cdfa7cf16..2eb4f058692d 100644
--- a/llvm/test/Transforms/InstCombine/fcmp.ll
+++ b/llvm/test/Transforms/InstCombine/fcmp.ll
@@ -49,3 +49,12 @@ define i1 @test6(float %x, float %y) nounwind {
 ; CHECK: @test6
 ; CHECK-NEXT: fcmp ogt float %x, %y
 }
+
+define i1 @test7(float %x) nounwind readnone ssp noredzone {
+  %ext = fpext float %x to ppc_fp128
+  %cmp = fcmp ogt ppc_fp128 %ext, 0xM00000000000000000000000000000000
+  ret i1 %cmp
+; Can't convert ppc_fp128
+; CHECK: @test7
+; CHECK-NEXT: fpext float %x to ppc_fp128
+}