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

Port 6470ddad

Original commit message:

    This introduces SilenceNaN operator, which makes sure that we only
    store quiet NaNs into holey arrays. We omit the NaN silencing code
    at instruction selection time if the input is an operation that
    cannot possibly produce signalling NaNs.

R=jarin@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Review-Url: https://codereview.chromium.org/2069883002
Cr-Commit-Position: refs/heads/master@{#36981}

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));

src/compiler/ppc/instruction-codes-ppc.h

@@ -93,6 +93,7 @@ namespace compiler {
   V(PPC_Uint32ToFloat32)           \
   V(PPC_Uint32ToDouble)            \
   V(PPC_Float32ToDouble)           \
+  V(PPC_Float64SilenceNaN)         \
   V(PPC_DoubleToInt32)             \
   V(PPC_DoubleToUint32)            \
   V(PPC_DoubleToInt64)             \

src/compiler/ppc/instruction-scheduler-ppc.cc

@@ -92,6 +92,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kPPC_Uint32ToFloat32:
     case kPPC_Uint32ToDouble:
     case kPPC_Float32ToDouble:
+    case kPPC_Float64SilenceNaN:
     case kPPC_DoubleToInt32:
     case kPPC_DoubleToUint32:
     case kPPC_DoubleToInt64:

src/compiler/ppc/instruction-selector-ppc.cc

@@ -1294,6 +1294,10 @@ void InstructionSelector::VisitFloat32Max(Node* node) { UNREACHABLE(); }
 
 void InstructionSelector::VisitFloat64Max(Node* node) { UNREACHABLE(); }
 
+void InstructionSelector::VisitFloat64SilenceNaN(Node* node) {
+  VisitRR(this, kPPC_Float64SilenceNaN, node);
+}
+
 
 void InstructionSelector::VisitFloat32Min(Node* node) { UNREACHABLE(); }