[builtins] Introduce proper Float64Log2 and Float64Log10 operators.

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

Index: src/compiler/mips/code-generator-mips.cc
diff --git a/src/compiler/mips/code-generator-mips.cc b/src/compiler/mips/code-generator-mips.cc
index bbf662fe0a1df9e1dfa45256a5946d59ebe8c103..792ddc01eb03af9e11c7033b227645c3bb76189c 100644
--- a/src/compiler/mips/code-generator-mips.cc
+++ b/src/compiler/mips/code-generator-mips.cc
@@ -753,6 +753,12 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
     case kIeee754Float64Log1p:
       ASSEMBLE_IEEE754_UNOP(log1p);
       break;
+    case kIeee754Float64Log2:
+      ASSEMBLE_IEEE754_UNOP(log2);
+      break;
+    case kIeee754Float64Log10:
+      ASSEMBLE_IEEE754_UNOP(log10);
+      break;
     case kMipsAdd:
       __ Addu(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;