Inline floating point compare

Inline floating point compare instead of calling the stub when the following conditions are met:
  * Code is in a loop
  * Compare is not a for loop condition
  * Compare is not an equal comparison

This inlined code handles heap number to heap number and heap number to smi compare. It can also handle smi to smi compare, but whenever there is a chance of comparing two smis the smi compare is inlined before the inlined floating point compare. Support for non SSE2 hardware is included.

A new set of variants of the compare stub without the floating point comparison code is called if the inline comapre fails due to the operands not beeing heap numbers or smis.

The virtual frame has been extended with a branch taking two live results to be carried through to the destination. This makes this change much simpler as the inlined code have two live results in registers and a number of bailouts.

CompareStub::GetName needs to be updated as well. I will do that as a separate change.

Also inlined equality check if both operands can't be NaN. This can only provide positive equals if it is the same object.
Review URL: http://codereview.chromium.org/1117011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4220 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/codegen-arm.cc

@@ -7159,10 +7159,11 @@ int CompareStub::MinorKey() {
   // Encode the three parameters in a unique 16 bit value. To avoid duplicate
   // stubs the never NaN NaN condition is only taken into account if the
   // condition is equals.
-  ASSERT((static_cast<unsigned>(cc_) >> 28) < (1 << 14));
+  ASSERT((static_cast<unsigned>(cc_) >> 28) < (1 << 13));
   return ConditionField::encode(static_cast<unsigned>(cc_) >> 28)
          | StrictField::encode(strict_)
-         | NeverNanNanField::encode(cc_ == eq ? never_nan_nan_ : false);
+         | NeverNanNanField::encode(cc_ == eq ? never_nan_nan_ : false)
+         | IncludeNumberCompareField::encode(include_number_compare_);
 }
 
 

src/codegen.h

@@ -346,8 +346,12 @@ class CompareStub: public CodeStub {
  public:
   CompareStub(Condition cc,
               bool strict,
-              NaNInformation nan_info = kBothCouldBeNaN) :
-      cc_(cc), strict_(strict), never_nan_nan_(nan_info == kCantBothBeNaN) { }
+              NaNInformation nan_info = kBothCouldBeNaN,
+              bool include_number_compare = true) :
+      cc_(cc),
+      strict_(strict),
+      never_nan_nan_(nan_info == kCantBothBeNaN),
+      include_number_compare_(include_number_compare) { }
 
   void Generate(MacroAssembler* masm);
 
@@ -360,11 +364,16 @@ class CompareStub: public CodeStub {
   // generating the minor key for other comparisons to avoid creating more
   // stubs.
   bool never_nan_nan_;
+  // Do generate the number comparison code in the stub. Stubs without number
+  // comparison code is used when the number comparison has been inlined, and
+  // the stub will be called if one of the operands is not a number.
+  bool include_number_compare_;
 
   // Encoding of the minor key CCCCCCCCCCCCCCNS.
   class StrictField: public BitField<bool, 0, 1> {};
   class NeverNanNanField: public BitField<bool, 1, 1> {};
-  class ConditionField: public BitField<int, 2, 14> {};
+  class IncludeNumberCompareField: public BitField<bool, 2, 1> {};
+  class ConditionField: public BitField<int, 3, 13> {};
 
   Major MajorKey() { return Compare; }
 

src/ia32/codegen-ia32.h

@@ -528,6 +528,10 @@ class CodeGenerator: public AstVisitor {
                   Condition cc,
                   bool strict,
                   ControlDestination* destination);
+  void GenerateInlineNumberComparison(Result* left_side,
+                                      Result* right_side,
+                                      Condition cc,
+                                      ControlDestination* dest);
 
   // To prevent long attacker-controlled byte sequences, integer constants
   // from the JavaScript source are loaded in two parts if they are larger

src/jump-target.cc

@@ -290,6 +290,25 @@ void JumpTarget::Branch(Condition cc, Result* arg, Hint hint) {
 }
 
 
+void JumpTarget::Branch(Condition cc, Result* arg0, Result* arg1, Hint hint) {
+  ASSERT(cgen()->has_valid_frame());
+
+  // We want to check that non-frame registers at the call site stay in
+  // the same registers on the fall-through branch.
+  DECLARE_ARGCHECK_VARS(arg0);
+  DECLARE_ARGCHECK_VARS(arg1);
+
+  cgen()->frame()->Push(arg0);
+  cgen()->frame()->Push(arg1);
+  DoBranch(cc, hint);
+  *arg1 = cgen()->frame()->Pop();
+  *arg0 = cgen()->frame()->Pop();
+
+  ASSERT_ARGCHECK(arg0);
+  ASSERT_ARGCHECK(arg1);
+}
+
+
 void BreakTarget::Branch(Condition cc, Result* arg, Hint hint) {
   ASSERT(cgen()->has_valid_frame());
 
@@ -331,6 +350,17 @@ void JumpTarget::Bind(Result* arg) {
 }
 
 
+void JumpTarget::Bind(Result* arg0, Result* arg1) {
+  if (cgen()->has_valid_frame()) {
+    cgen()->frame()->Push(arg0);
+    cgen()->frame()->Push(arg1);
+  }
+  DoBind();
+  *arg1 = cgen()->frame()->Pop();
+  *arg0 = cgen()->frame()->Pop();
+}
+
+
 void JumpTarget::AddReachingFrame(VirtualFrame* frame) {
   ASSERT(reaching_frames_.length() == merge_labels_.length());
   ASSERT(entry_frame_ == NULL);

src/jump-target.h

@@ -117,12 +117,17 @@ class JumpTarget : public ZoneObject {  // Shadows are dynamically allocated.
   // the target and the fall-through.
   virtual void Branch(Condition cc, Hint hint = no_hint);
   virtual void Branch(Condition cc, Result* arg, Hint hint = no_hint);
+  virtual void Branch(Condition cc,
+                      Result* arg0,
+                      Result* arg1,
+                      Hint hint = no_hint);
 
   // Bind a jump target.  If there is no current frame at the binding
   // site, there must be at least one frame reaching via a forward
   // jump.
   virtual void Bind();
   virtual void Bind(Result* arg);
+  virtual void Bind(Result* arg0, Result* arg1);
 
   // Emit a call to a jump target.  There must be a current frame at
   // the call.  The frame at the target is the same as the current

src/x64/codegen-x64.cc

@@ -9105,10 +9105,11 @@ int CompareStub::MinorKey() {
   // Encode the three parameters in a unique 16 bit value. To avoid duplicate
   // stubs the never NaN NaN condition is only taken into account if the
   // condition is equals.
-  ASSERT(static_cast<unsigned>(cc_) < (1 << 14));
+  ASSERT(static_cast<unsigned>(cc_) < (1 << 13));
   return ConditionField::encode(static_cast<unsigned>(cc_))
          | StrictField::encode(strict_)
-         | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false);
+         | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false)
+         | IncludeNumberCompareField::encode(include_number_compare_);
 }