[turbofan] Fix input count in Uint32Mod/Div reduction.

src/compiler/machine-operator-reducer.cc

Index: src/compiler/machine-operator-reducer.cc
diff --git a/src/compiler/machine-operator-reducer.cc b/src/compiler/machine-operator-reducer.cc
index a40da1360cfbfb3dc23f5ce05e75b2b1dbd4e4a4..aaf32bc07f208e56c0a44f8974932f86b3d08d9b 100644
--- a/src/compiler/machine-operator-reducer.cc
+++ b/src/compiler/machine-operator-reducer.cc
@@ -600,8 +600,9 @@ Reduction MachineOperatorReducer::ReduceUint32Div(Node* node) {
     return Replace(Word32Equal(Word32Equal(m.left().node(), zero), zero));
   }
   if (m.right().IsPowerOf2()) {  // x / 2^n => x >> n
-    node->set_op(machine()->Word32Shr());
     node->ReplaceInput(1, Uint32Constant(WhichPowerOf2(m.right().Value())));

[Benedikt Meurer, 2014/10/29 18:26:45]

Let's keep the set_op() before ReplaceInput.

[Jarin, 2014/10/29 21:12:24]

Done.

I am wondering what's the reason for this. I was always imagining that the
set_op method should be the operation that morally 'commits' the changes to the
node. E.g., if we want to hook up the typer for re-typing, set_op would be the
method to do that. (Well, we would have to make set_op a method on the graph,
but you get the idea.)

+    node->TrimInputCount(2);
+    node->set_op(machine()->Word32Shr());
     return Changed(node);
   }
   return NoChange();
@@ -665,8 +666,9 @@ Reduction MachineOperatorReducer::ReduceUint32Mod(Node* node) {
         base::bits::UnsignedMod32(m.left().Value(), m.right().Value()));
   }
   if (m.right().IsPowerOf2()) {  // x % 2^n => x & 2^n-1
-    node->set_op(machine()->Word32And());
     node->ReplaceInput(1, Uint32Constant(m.right().Value() - 1));
+    node->TrimInputCount(2);
+    node->set_op(machine()->Word32And());

[Benedikt Meurer, 2014/10/29 18:26:45]

Same here.

[Jarin, 2014/10/29 21:12:24]

Done.

     return Changed(node);
   }
   return NoChange();