[builtins] Introduce proper Float64Atan and Float64Atan2 operators.

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

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index 2f3c791cf791def1f7d96c4bfe9f28c7649aaccc..36617a992ea035cb9729bd178c6ce1f31b410a00 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -934,6 +934,14 @@ void InstructionSelector::VisitFloat32Neg(Node* node) { UNREACHABLE(); }
 
 void InstructionSelector::VisitFloat64Neg(Node* node) { UNREACHABLE(); }
 
+void InstructionSelector::VisitFloat64Ieee754Binop(Node* node,
+                                                   InstructionCode opcode) {
+  MipsOperandGenerator g(this);
+  Emit(opcode, g.DefineAsFixed(node, f0), g.UseFixed(node->InputAt(0), f12),
+       g.UseFixed(node->InputAt(1), f14))
+      ->MarkAsCall();
+}
+
 void InstructionSelector::VisitFloat64Ieee754Unop(Node* node,
                                                   InstructionCode opcode) {
   MipsOperandGenerator g(this);