Make x87 stack tracking more robust and avoid spilling

src/ia32/lithium-ia32.h

Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index a6a25261ea446c6457a16bea6521f0e468e80e07..0c2f8a0bbf4195e251c275e98e4648f54603e538 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -276,10 +276,7 @@ class LInstruction : public ZoneObject {
   bool ClobbersTemps() const { return IsCall(); }
   bool ClobbersRegisters() const { return IsCall(); }
   virtual bool ClobbersDoubleRegisters() const {
-    return IsCall() ||
-           // We only have rudimentary X87Stack tracking, thus in general
-           // cannot handle phi-nodes.
-           (!CpuFeatures::IsSafeForSnapshot(SSE2) && IsControl());
+    return IsCall();
   }
 
   virtual bool HasResult() const = 0;
@@ -408,17 +405,18 @@ class LInstructionGap V8_FINAL : public LGap {
 
 class LGoto V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
-  explicit LGoto(int block_id) : block_id_(block_id) { }
+  explicit LGoto(HBasicBlock* block) : block_(block) { }
 
   virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   virtual bool IsControl() const V8_OVERRIDE { return true; }
 
-  int block_id() const { return block_id_; }
+  int block_id() const { return block_->block_id(); }
+  HBasicBlock* block() const { return block_; }
 
  private:
-  int block_id_;
+  HBasicBlock* block_;
 };