[turbofan] Spill rsi and rdi in their existing locations.

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index eac5571e9c4b8ae1424aab36d9690efb941a5db0..39db29890b19c9643d429182447557e3f84c2070 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -1082,9 +1082,19 @@ void InstructionSelector::VisitGuard(Node* node) {
 void InstructionSelector::VisitParameter(Node* node) {
   OperandGenerator g(this);
   int index = ParameterIndexOf(node->op());
-  Emit(kArchNop,
-       g.DefineAsLocation(node, linkage()->GetParameterLocation(index),
-                          linkage()->GetParameterType(index)));
+  InstructionOperand op =
+      g.DefineAsLocation(node, linkage()->GetParameterLocation(index),
+                         linkage()->GetParameterType(index));
+
+  if (linkage()->ParameterHasSecondaryLocation(index)) {
+    InstructionOperand prespilled = g.DefineAsLocation(

[Jarin, 2015/11/12 12:08:33]

I am mildly surprised that it is possible to define the same node twice. Could
you add a comment here explaining why we do that?

[Mircea Trofin, 2015/11/12 18:01:35]

Will do - if we keep this design.

+        node, linkage()->GetParameterSecondaryLocation(index),
+        linkage()->GetParameterType(index));
+    InstructionOperand outputs[2] = {op, prespilled};
+    Emit(kArchNop, 2, outputs, 0, nullptr);
+  } else {
+    Emit(kArchNop, op);
+  }
 }