Fix MathFloorOfDiv optimization on non-SDIV ARM

src/hydrogen-instructions.cc

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@@ skipping 1532 matching lines @@
       HValue* new_left = SimplifiedDividendForMathFloorOfDiv(left);
       if (new_left == NULL &&
           hdiv->observed_input_representation(1).IsSmiOrInteger32()) {
         new_left = new(block()->zone())
             HChange(left, Representation::Integer32(), false, false);
         HChange::cast(new_left)->InsertBefore(this);
       }
       HValue* new_right =
           LChunkBuilder::SimplifiedDivisorForMathFloorOfDiv(right);
       if (new_right == NULL &&
+#ifdef V8_TARGET_ARCH_ARM

[Sven Panne, 2013/06/14 20:05:25]

o_O I think we're doing something fundamentally wrong here if we use
target-specific #ifdefs. It's OK for a temporary quick-n-dirty (performance?
can't even tell...) fix to get things landed, but this should be removed as
quickly as possible at all cost (no idea how, let's talk next week).

We already have the ugly #ifdef wart because of the non-uniform handling of the
context register here, we should improve things and not make it worse.

+          CpuFeatures::IsSupported(SUDIV) &&
+#endif
           hdiv->observed_input_representation(2).IsSmiOrInteger32()) {
         new_right = new(block()->zone())
             HChange(right, Representation::Integer32(), false, false);
         HChange::cast(new_right)->InsertBefore(this);
       }
 
       // Return if left or right are not optimizable.
       if ((new_left == NULL) || (new_right == NULL)) return this;
 
       // Insert the new values in the graph.
@@ skipping 2303 matching lines @@
     case kBackingStore:
       if (!name_.is_null()) stream->Add(*String::cast(*name_)->ToCString());
       stream->Add("[backing-store]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal