[wasm] Use MachineOperator::Float64Log to implement kExprF64Log.

R=titzer@chromium.org, bmeurer@chromium.org

BUG=v8:5065

Review-Url: https://codereview.chromium.org/2036143002
Cr-Commit-Position: refs/heads/master@{#36709}

src/assembler.cc

@@ -1351,15 +1351,6 @@ ExternalReference ExternalReference::f64_exp_wrapper_function(
   return ExternalReference(Redirect(isolate, FUNCTION_ADDR(f64_exp_wrapper)));
 }
 
-static void f64_log_wrapper(double* param) {
-  WriteDoubleValue(param, std::log(ReadDoubleValue(param)));
-}
-
-ExternalReference ExternalReference::f64_log_wrapper_function(
-    Isolate* isolate) {
-  return ExternalReference(Redirect(isolate, FUNCTION_ADDR(f64_log_wrapper)));
-}
-
 static void f64_pow_wrapper(double* param0, double* param1) {
   WriteDoubleValue(param0, power_double_double(ReadDoubleValue(param0),
                                                ReadDoubleValue(param1)));

src/assembler.h

@@ -973,7 +973,6 @@ class ExternalReference BASE_EMBEDDED {
   static ExternalReference f64_sin_wrapper_function(Isolate* isolate);
   static ExternalReference f64_tan_wrapper_function(Isolate* isolate);
   static ExternalReference f64_exp_wrapper_function(Isolate* isolate);
-  static ExternalReference f64_log_wrapper_function(Isolate* isolate);
   static ExternalReference f64_atan2_wrapper_function(Isolate* isolate);
   static ExternalReference f64_pow_wrapper_function(Isolate* isolate);
   static ExternalReference f64_mod_wrapper_function(Isolate* isolate);

src/compiler/wasm-compiler.cc

@@ -796,9 +796,9 @@ Node* WasmGraphBuilder::Unop(wasm::WasmOpcode opcode, Node* input,
     case wasm::kExprF64Exp: {
       return BuildF64Exp(input);
     }
-    case wasm::kExprF64Log: {
-      return BuildF64Log(input);
-    }
+    case wasm::kExprF64Log:
+      op = m->Float64Log();
+      break;
     case wasm::kExprI32ConvertI64:
       op = m->TruncateInt64ToInt32();
       break;
@@ -1383,13 +1383,6 @@ Node* WasmGraphBuilder::BuildF64Exp(Node* input) {
   return BuildCFuncInstruction(ref, type, input);
 }
 
-Node* WasmGraphBuilder::BuildF64Log(Node* input) {
-  MachineType type = MachineType::Float64();
-  ExternalReference ref =
-      ExternalReference::f64_log_wrapper_function(jsgraph()->isolate());
-  return BuildCFuncInstruction(ref, type, input);
-}
-
 Node* WasmGraphBuilder::BuildF64Atan2(Node* left, Node* right) {
   MachineType type = MachineType::Float64();
   ExternalReference ref =

src/compiler/wasm-compiler.h

@@ -280,7 +280,6 @@ class WasmGraphBuilder {
   Node* BuildF64Sin(Node* input);
   Node* BuildF64Tan(Node* input);
   Node* BuildF64Exp(Node* input);
-  Node* BuildF64Log(Node* input);
   Node* BuildF64Pow(Node* left, Node* right);
   Node* BuildF64Atan2(Node* left, Node* right);
   Node* BuildF64Mod(Node* left, Node* right);

src/external-reference-table.cc

@@ -158,8 +158,6 @@ ExternalReferenceTable::ExternalReferenceTable(Isolate* isolate) {
       "f64_tan_wrapper");
   Add(ExternalReference::f64_exp_wrapper_function(isolate).address(),
       "f64_exp_wrapper");
-  Add(ExternalReference::f64_log_wrapper_function(isolate).address(),
-      "f64_log_wrapper");
   Add(ExternalReference::f64_pow_wrapper_function(isolate).address(),
       "f64_pow_wrapper");
   Add(ExternalReference::f64_atan2_wrapper_function(isolate).address(),