Reland r10908 (Ensure consistent result of transcendental function0.)

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 982639e9a56094d863d53e3bbb8d123284a05a72..2bfb0043bc50c6beaea831b862c2abff02669b18 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -1628,7 +1628,7 @@ void TranscendentalCacheStub::Generate(MacroAssembler* masm) {
     __ movsd(FieldOperand(rax, HeapNumber::kValueOffset), xmm1);
     __ fld_d(FieldOperand(rax, HeapNumber::kValueOffset));
   }
-  GenerateOperation(masm);
+  GenerateOperation(masm, type_);
   __ movq(Operand(rcx, 0), rbx);
   __ movq(Operand(rcx, 2 * kIntSize), rax);
   __ fstp_d(FieldOperand(rax, HeapNumber::kValueOffset));
@@ -1643,7 +1643,7 @@ void TranscendentalCacheStub::Generate(MacroAssembler* masm) {
     __ subq(rsp, Immediate(kDoubleSize));
     __ movsd(Operand(rsp, 0), xmm1);
     __ fld_d(Operand(rsp, 0));
-    GenerateOperation(masm);
+    GenerateOperation(masm, type_);
     __ fstp_d(Operand(rsp, 0));
     __ movsd(xmm1, Operand(rsp, 0));
     __ addq(rsp, Immediate(kDoubleSize));
@@ -1695,16 +1695,17 @@ Runtime::FunctionId TranscendentalCacheStub::RuntimeFunction() {
 }
 
 
-void TranscendentalCacheStub::GenerateOperation(MacroAssembler* masm) {
+void TranscendentalCacheStub::GenerateOperation(
+    MacroAssembler* masm, TranscendentalCache::Type type) {
   // Registers:
   // rax: Newly allocated HeapNumber, which must be preserved.
   // rbx: Bits of input double. Must be preserved.
   // rcx: Pointer to cache entry. Must be preserved.
   // st(0): Input double
   Label done;
-  if (type_ == TranscendentalCache::SIN ||
-      type_ == TranscendentalCache::COS ||
-      type_ == TranscendentalCache::TAN) {
+  if (type == TranscendentalCache::SIN ||
+      type == TranscendentalCache::COS ||
+      type == TranscendentalCache::TAN) {
     // Both fsin and fcos require arguments in the range +/-2^63 and
     // return NaN for infinities and NaN. They can share all code except
     // the actual fsin/fcos operation.
@@ -1725,8 +1726,12 @@ void TranscendentalCacheStub::GenerateOperation(MacroAssembler* masm) {
     __ j(not_equal, &non_nan_result, Label::kNear);
     // Input is +/-Infinity or NaN. Result is NaN.
     __ fstp(0);
-    __ LoadRoot(kScratchRegister, Heap::kNanValueRootIndex);
-    __ fld_d(FieldOperand(kScratchRegister, HeapNumber::kValueOffset));
+    // NaN is represented by 0x7ff8000000000000.

[Yang, 2012/03/03 11:05:01]

Loading NaN from the root list won't work if we are calling this piece of code
as a C function. Instead we just load the bit pattern for NaN just like we do in
the ia32 version of this.

[Sven Panne, 2012/03/05 07:45:47]

I think the cleaner and more consistent way would be leaving the code here as it
was before, and call InitializeRootRegister in the code generated in
CreateTranscendentalFunction instead.

+    __ subq(rsp, Immediate(kPointerSize));
+    __ movl(Operand(rsp, 4), Immediate(0x7ff80000));
+    __ movl(Operand(rsp, 0), Immediate(0x00000000));
+    __ fld_d(Operand(rsp, 0));
+    __ addq(rsp, Immediate(kPointerSize));
     __ jmp(&done);
 
     __ bind(&non_nan_result);
@@ -1767,7 +1772,7 @@ void TranscendentalCacheStub::GenerateOperation(MacroAssembler* masm) {
     // FPU Stack: input % 2*pi
     __ movq(rax, rdi);  // Restore rax, pointer to the new HeapNumber.
     __ bind(&in_range);
-    switch (type_) {
+    switch (type) {
       case TranscendentalCache::SIN:
         __ fsin();
         break;
@@ -1785,7 +1790,7 @@ void TranscendentalCacheStub::GenerateOperation(MacroAssembler* masm) {
     }
     __ bind(&done);
   } else {
-    ASSERT(type_ == TranscendentalCache::LOG);
+    ASSERT(type == TranscendentalCache::LOG);
     __ fldln2();
     __ fxch();
     __ fyl2x();