Fix for an ARM register allocation bug.

src/arm/lithium-gap-resolver-arm.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 "arm/lithium-gap-resolver-arm.h"
 #include "arm/lithium-codegen-arm.h"
 
 namespace v8 {
 namespace internal {
 
 static const Register kSavedValueRegister = { 9 };
-static const DoubleRegister kSavedDoubleValueRegister = { 0 };
 
 LGapResolver::LGapResolver(LCodeGen* owner)
     : cgen_(owner), moves_(32), root_index_(0), in_cycle_(false),
       saved_destination_(NULL) { }
 
 
 void LGapResolver::Resolve(LParallelMove* parallel_move) {
   ASSERT(moves_.is_empty());
   // Build up a worklist of moves.
   BuildInitialMoveList(parallel_move);
@@ skipping 117 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()) {
     __ ldr(kSavedValueRegister, cgen_->ToMemOperand(source));
   } else if (source->IsDoubleRegister()) {
-    __ vmov(kSavedDoubleValueRegister, cgen_->ToDoubleRegister(source));
+    __ vmov(kScratchDoubleReg, cgen_->ToDoubleRegister(source));
   } else if (source->IsDoubleStackSlot()) {
-    __ vldr(kSavedDoubleValueRegister, cgen_->ToMemOperand(source));
+    __ vldr(kScratchDoubleReg, 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.
   if (saved_destination_->IsRegister()) {
     __ mov(cgen_->ToRegister(saved_destination_), kSavedValueRegister);
   } else if (saved_destination_->IsStackSlot()) {
     __ str(kSavedValueRegister, cgen_->ToMemOperand(saved_destination_));
   } else if (saved_destination_->IsDoubleRegister()) {
-    __ vmov(cgen_->ToDoubleRegister(saved_destination_),
-            kSavedDoubleValueRegister);
+    __ vmov(cgen_->ToDoubleRegister(saved_destination_), kScratchDoubleReg);
   } else if (saved_destination_->IsDoubleStackSlot()) {
-    __ vstr(kSavedDoubleValueRegister,
-            cgen_->ToMemOperand(saved_destination_));
+    __ vstr(kScratchDoubleReg, cgen_->ToMemOperand(saved_destination_));
   } else {
     UNREACHABLE();
   }
 
   in_cycle_ = false;
   saved_destination_ = NULL;
 }
 
 
 void LGapResolver::EmitMove(int index) {
@@ skipping 17 matching lines @@
     if (destination->IsRegister()) {
       __ ldr(cgen_->ToRegister(destination), source_operand);
     } else {
       ASSERT(destination->IsStackSlot());
       MemOperand destination_operand = cgen_->ToMemOperand(destination);
       if (in_cycle_) {
         if (!destination_operand.OffsetIsUint12Encodable()) {
           // ip is overwritten while saving the value to the destination.
           // Therefore we can't use ip.  It is OK if the read from the source
           // destroys ip, since that happens before the value is read.
-          __ vldr(kSavedDoubleValueRegister.low(), source_operand);
-          __ vstr(kSavedDoubleValueRegister.low(), destination_operand);
+          __ vldr(kScratchDoubleReg.low(), source_operand);
+          __ vstr(kScratchDoubleReg.low(), destination_operand);
         } else {
           __ ldr(ip, source_operand);
           __ str(ip, destination_operand);
         }
       } else {
         __ ldr(kSavedValueRegister, source_operand);
         __ str(kSavedValueRegister, destination_operand);
       }
     }
 
@@ skipping 40 matching lines @@
         // but kSavedValueRegister is free.
         MemOperand source_high_operand =
             cgen_->ToHighMemOperand(source);
         MemOperand destination_high_operand =
             cgen_->ToHighMemOperand(destination);
         __ ldr(kSavedValueRegister, source_operand);
         __ str(kSavedValueRegister, destination_operand);
         __ ldr(kSavedValueRegister, source_high_operand);
         __ str(kSavedValueRegister, destination_high_operand);
       } else {
-        __ vldr(kSavedDoubleValueRegister, source_operand);
-        __ vstr(kSavedDoubleValueRegister, destination_operand);
+        __ vldr(kScratchDoubleReg, source_operand);
+        __ vstr(kScratchDoubleReg, destination_operand);
       }
     }
   } else {
     UNREACHABLE();
   }
 
   moves_[index].Eliminate();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal