PPC: [builtins] Migrate Math.log to TurboFan.

Port f2da19fe

Original commit message:

    Introduce a dedicated Float64Log machine operator, that is either
    implemented by a direct C call or by platform specific code, i.e.
    using the FPU on x64 and ia32.

    This operator is used to implement Math.log as a proper TurboFan
    builtin on top of the CodeStubAssembler.

    Also introduce a NumberLog simplified operator on top of Float64Log
    and use that for the fast inline path of Math.log inside TurboFan
    optimized code.

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

BUG=v8:5065
LOG=N

Review-Url: https://codereview.chromium.org/2036273002
Cr-Commit-Position: refs/heads/master@{#36720}

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

@@ -437,6 +437,17 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
   } while (0)
 
 
+#define ASSEMBLE_FLOAT_LOG()                                                  \
+  do {                                                                        \
+    FrameScope scope(masm(), StackFrame::MANUAL);                             \
+    __ PrepareCallCFunction(0, 1, kScratchReg);                               \
+    __ MovToFloatParameter(i.InputDoubleRegister(0));                        \
+    __ CallCFunction(ExternalReference::math_log_double_function(isolate()),  \
+                     0, 1);                                                   \
+    __ MovFromFloatResult(i.OutputDoubleRegister());                          \
+    DCHECK_EQ(LeaveRC, i.OutputRCBit());                                      \
+  } while (0)
+
 #define ASSEMBLE_FLOAT_MAX(scratch_reg)                                       \
   do {                                                                        \
     __ fsub(scratch_reg, i.InputDoubleRegister(0), i.InputDoubleRegister(1)); \
@@ -1229,6 +1240,11 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       // and generate a CallAddress instruction instead.
       ASSEMBLE_FLOAT_MODULO();
       break;
+    case kPPC_LogDouble:
+      // TODO(bmeurer): We should really get rid of this special instruction,
+      // and generate a CallAddress instruction instead.
+      ASSEMBLE_FLOAT_LOG();
+      break;
     case kPPC_Neg:
       __ neg(i.OutputRegister(), i.InputRegister(0), LeaveOE, i.OutputRCBit());
       break;

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

@@ -57,6 +57,7 @@ namespace compiler {
   V(PPC_ModU32)                    \
   V(PPC_ModU64)                    \
   V(PPC_ModDouble)                 \
+  V(PPC_LogDouble)                 \
   V(PPC_Neg)                       \
   V(PPC_NegDouble)                 \
   V(PPC_SqrtDouble)                \

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

@@ -59,6 +59,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kPPC_ModU32:
     case kPPC_ModU64:
     case kPPC_ModDouble:
+    case kPPC_LogDouble:
     case kPPC_Neg:
     case kPPC_NegDouble:
     case kPPC_SqrtDouble:

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

@@ -1310,6 +1310,11 @@ void InstructionSelector::VisitFloat64Abs(Node* node) {
   VisitRR(this, kPPC_AbsDouble, node);
 }
 
+void InstructionSelector::VisitFloat64Log(Node* node) {
+  PPCOperandGenerator g(this);
+  Emit(kPPC_LogDouble, g.DefineAsFixed(node, d1),
+       g.UseFixed(node->InputAt(0), d1))->MarkAsCall();
+}
 
 void InstructionSelector::VisitFloat32Sqrt(Node* node) {
   VisitRR(this, kPPC_SqrtDouble | MiscField::encode(1), node);