[turbofan] Introduce Float64Pow and NumberPow operators.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 0158369f756b89586126dc2d4530662433a672fe..c91df28e0089337a86b99d2583309d8c826173ce 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -2561,6 +2561,20 @@ void Builtins::Generate_MathRound(CodeStubAssembler* assembler) {
   Generate_MathRoundingOperation(assembler, &CodeStubAssembler::Float64Round);
 }
 
+// ES6 section 20.2.2.26 Math.pow ( x, y )
+void Builtins::Generate_MathPow(CodeStubAssembler* assembler) {
+  using compiler::Node;
+
+  Node* x = assembler->Parameter(1);
+  Node* y = assembler->Parameter(2);
+  Node* context = assembler->Parameter(5);
+  Node* x_value = assembler->TruncateTaggedToFloat64(context, x);
+  Node* y_value = assembler->TruncateTaggedToFloat64(context, y);
+  Node* value = assembler->Float64Pow(x_value, y_value);
+  Node* result = assembler->ChangeFloat64ToTagged(value);
+  assembler->Return(result);
+}
+
 // ES6 section 20.2.2.30 Math.sin ( x )
 void Builtins::Generate_MathSin(CodeStubAssembler* assembler) {
   using compiler::Node;