Fix pattern detection for replacing shifts by rotation.

src/hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 8446 matching lines @@
   HInstruction* checked_index =
       AddInstruction(new(zone()) HBoundsCheck(index, length));
   return new(zone()) HStringCharCodeAt(context, string, checked_index);
 }
 
 // Checks if the given shift amounts have form: (sa) and (32 - sa).
 static bool ShiftAmountsAllowReplaceByRotate(HValue* sa,
                                              HValue* const32_minus_sa) {
   if (!const32_minus_sa->IsSub()) return false;
   HSub* sub = HSub::cast(const32_minus_sa);
+  if (sa != sub->right()) return false;
   HValue* const32 = sub->left();
   if (!const32->IsConstant() ||
       HConstant::cast(const32)->Integer32Value() != 32) {
     return false;
   }
   return (sub->right() == sa);
 }
 
 
 // Checks if the left and the right are shift instructions with the oposite
 // directions that can be replaced by one rotate right instruction or not.
 // Returns the operand and the shift amount for the rotate instruction in the
 // former case.
 bool HOptimizedGraphBuilder::MatchRotateRight(HValue* left,
                                               HValue* right,
                                               HValue** operand,
                                               HValue** shift_amount) {
   HShl* shl;
   HShr* shr;
   if (left->IsShl() && right->IsShr()) {
     shl = HShl::cast(left);
     shr = HShr::cast(right);
   } else if (left->IsShr() && right->IsShl()) {
     shl = HShl::cast(right);
     shr = HShr::cast(left);
   } else {
     return false;
   }
+  if (shl->left() != shr->left()) return false;
 
   if (!ShiftAmountsAllowReplaceByRotate(shl->right(), shr->right()) &&
       !ShiftAmountsAllowReplaceByRotate(shr->right(), shl->right())) {
     return false;
   }
   *operand= shr->left();
   *shift_amount = shr->right();
   return true;
 }
 
@@ skipping 1796 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal