MIPS: Fix for an ARM register allocation bug.

src/mips/lithium-gap-resolver-mips.cc

-// Copyright 2011 the V8 project authors. All rights reserved.
+// 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
 //       with the distribution.
@@ skipping 15 matching lines @@
 
 #include "v8.h"
 
 #include "mips/lithium-gap-resolver-mips.h"
 #include "mips/lithium-codegen-mips.h"
 
 namespace v8 {
 namespace internal {
 
 static const Register kSavedValueRegister = kLithiumScratchReg;
-static const DoubleRegister kSavedDoubleValueRegister = kLithiumScratchDouble;
 
 LGapResolver::LGapResolver(LCodeGen* owner)
     : cgen_(owner),
       moves_(32),
       root_index_(0),
       in_cycle_(false),
       saved_destination_(NULL) {}
 
 
 void LGapResolver::Resolve(LParallelMove* parallel_move) {
@@ skipping 120 matching lines @@
   ASSERT(moves_[index].destination()->Equals(moves_[root_index_].source()));
   ASSERT(!in_cycle_);
   in_cycle_ = true;
   LOperand* source = moves_[index].source();
   saved_destination_ = moves_[index].destination();
   if (source->IsRegister()) {
     __ mov(kSavedValueRegister, cgen_->ToRegister(source));
   } else if (source->IsStackSlot()) {
     __ lw(kSavedValueRegister, cgen_->ToMemOperand(source));
   } else if (source->IsDoubleRegister()) {
-    __ mov_d(kSavedDoubleValueRegister, cgen_->ToDoubleRegister(source));
+    __ mov_d(kLithiumScratchDouble, cgen_->ToDoubleRegister(source));
   } else if (source->IsDoubleStackSlot()) {
-    __ ldc1(kSavedDoubleValueRegister, cgen_->ToMemOperand(source));
+    __ ldc1(kLithiumScratchDouble, cgen_->ToMemOperand(source));
   } else {
     UNREACHABLE();
   }
   // This move will be done by restoring the saved value to the destination.
   moves_[index].Eliminate();
 }
 
 
 void LGapResolver::RestoreValue() {
   ASSERT(in_cycle_);
   ASSERT(saved_destination_ != NULL);
 
-  // Spilled value is in kSavedValueRegister or kSavedDoubleValueRegister.
+  // Spilled value is in kSavedValueRegister or kLithiumScratchDouble.
   if (saved_destination_->IsRegister()) {
     __ mov(cgen_->ToRegister(saved_destination_), kSavedValueRegister);
   } else if (saved_destination_->IsStackSlot()) {
     __ sw(kSavedValueRegister, cgen_->ToMemOperand(saved_destination_));
   } else if (saved_destination_->IsDoubleRegister()) {
     __ mov_d(cgen_->ToDoubleRegister(saved_destination_),
-            kSavedDoubleValueRegister);
+            kLithiumScratchDouble);
   } else if (saved_destination_->IsDoubleStackSlot()) {
-    __ sdc1(kSavedDoubleValueRegister,
+    __ sdc1(kLithiumScratchDouble,
             cgen_->ToMemOperand(saved_destination_));
   } else {
     UNREACHABLE();
   }
 
   in_cycle_ = false;
   saved_destination_ = NULL;
 }
 
 
@@ skipping 19 matching lines @@
       __ lw(cgen_->ToRegister(destination), source_operand);
     } else {
       ASSERT(destination->IsStackSlot());
       MemOperand destination_operand = cgen_->ToMemOperand(destination);
       if (in_cycle_) {
         if (!destination_operand.OffsetIsInt16Encodable()) {
           // 'at' is overwritten while saving the value to the destination.
           // Therefore we can't use 'at'.  It is OK if the read from the source
           // destroys 'at', since that happens before the value is read.
           // This uses only a single reg of the double reg-pair.
-          __ lwc1(kSavedDoubleValueRegister, source_operand);
-          __ swc1(kSavedDoubleValueRegister, destination_operand);
+          __ lwc1(kLithiumScratchDouble, source_operand);
+          __ swc1(kLithiumScratchDouble, destination_operand);
         } else {
           __ lw(at, source_operand);
           __ sw(at, destination_operand);
         }
       } else {
         __ lw(kSavedValueRegister, source_operand);
         __ sw(kSavedValueRegister, destination_operand);
       }
     }
 
@@ skipping 30 matching lines @@
     }
 
   } else if (source->IsDoubleStackSlot()) {
     MemOperand source_operand = cgen_->ToMemOperand(source);
     if (destination->IsDoubleRegister()) {
       __ ldc1(cgen_->ToDoubleRegister(destination), source_operand);
     } else {
       ASSERT(destination->IsDoubleStackSlot());
       MemOperand destination_operand = cgen_->ToMemOperand(destination);
       if (in_cycle_) {
-        // kSavedDoubleValueRegister was used to break the cycle,
+        // kLithiumScratchDouble was used to break the cycle,
         // but kSavedValueRegister is free.
         MemOperand source_high_operand =
             cgen_->ToHighMemOperand(source);
         MemOperand destination_high_operand =
             cgen_->ToHighMemOperand(destination);
         __ lw(kSavedValueRegister, source_operand);
         __ sw(kSavedValueRegister, destination_operand);
         __ lw(kSavedValueRegister, source_high_operand);
         __ sw(kSavedValueRegister, destination_high_operand);
       } else {
-        __ ldc1(kSavedDoubleValueRegister, source_operand);
-        __ sdc1(kSavedDoubleValueRegister, destination_operand);
+        __ ldc1(kLithiumScratchDouble, source_operand);
+        __ sdc1(kLithiumScratchDouble, destination_operand);
       }
     }
   } else {
     UNREACHABLE();
   }
 
   moves_[index].Eliminate();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal