PPC: [turbofan] Prevent storing signalling NaNs into holey double arrays.

src/compiler/ppc/code-generator-ppc.cc

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index a994b53947cc84d85d0d92f570004b3f1df52043..b03ff475ebd85570ce1f4068c5c750f6ee43fa1c 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -1351,6 +1351,12 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       DCHECK_EQ(SetRC, i.OutputRCBit());
       break;
 #endif
+    case kPPC_Float64SilenceNaN: {
+      DoubleRegister value = i.InputDoubleRegister(0);
+      DoubleRegister result = i.OutputDoubleRegister();
+      __ CanonicalizeNaN(result, value);
+      break;
+    }
     case kPPC_Push:
       if (instr->InputAt(0)->IsFPRegister()) {
         __ stfdu(i.InputDoubleRegister(0), MemOperand(sp, -kDoubleSize));