X87: fix the Sqrt issue.

   The test mjsunit/regress/regress-sqrt compares the result of Math.sqrt function
   when using full-compiler and crankshaft compiler seperately. But according to
   glibc bug fixing(https://sourceware.org/bugzilla/show_bug.cgi?id=14032). The
   glibc implementation of std::sqrt() (It is invoked in the generated code when
   full-compiler is used.) will change since glibc 2.19.

   In order to keep consistence of Math.sqrt translation in crankshaft compiler
   and the pass of mjsunit/regress/regress-sqrt. we translate the Math.sqrt func
   by calling the runtime function.

BUG=
R=weiliang.lin@intel.com

Review URL: https://codereview.chromium.org/606403002

Patch from Chunyang Dai <chunyang.dai@intel.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24271 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x87/lithium-codegen-x87.cc

@@ -4021,12 +4021,65 @@ void LCodeGen::DoMathFround(LMathFround* instr) {
 
 
 void LCodeGen::DoMathSqrt(LMathSqrt* instr) {
-  X87Register input_reg = ToX87Register(instr->value());
-  X87Register output_reg = ToX87Register(instr->result());
-  DCHECK(output_reg.is(input_reg));
-  USE(output_reg);
-  X87Fxch(input_reg);
-  __ fsqrt();
+  X87Register input = ToX87Register(instr->value());
+  X87Register result_reg = ToX87Register(instr->result());
+  Register temp_result = ToRegister(instr->temp1());
+  Register temp = ToRegister(instr->temp2());
+  Label slow, done, smi, finish;
+  DCHECK(result_reg.is(input));
+
+  // Store input into Heap number and call runtime function kMathExpRT.
+  if (FLAG_inline_new) {
+    __ AllocateHeapNumber(temp_result, temp, no_reg, &slow);
+    __ jmp(&done, Label::kNear);
+  }
+
+  // Slow case: Call the runtime system to do the number allocation.
+  __ bind(&slow);
+  {
+    // TODO(3095996): Put a valid pointer value in the stack slot where the
+    // result register is stored, as this register is in the pointer map, but
+    // contains an integer value.
+    __ Move(temp_result, Immediate(0));
+
+    // Preserve the value of all registers.
+    PushSafepointRegistersScope scope(this);
+
+    __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
+    __ CallRuntimeSaveDoubles(Runtime::kAllocateHeapNumber);
+    RecordSafepointWithRegisters(
+       instr->pointer_map(), 0, Safepoint::kNoLazyDeopt);
+    __ StoreToSafepointRegisterSlot(temp_result, eax);
+  }
+  __ bind(&done);
+  X87LoadForUsage(input);
+  __ fstp_d(FieldOperand(temp_result, HeapNumber::kValueOffset));
+
+  {
+    // Preserve the value of all registers.
+    PushSafepointRegistersScope scope(this);
+
+    __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
+    __ push(temp_result);
+    __ CallRuntimeSaveDoubles(Runtime::kMathSqrtRT);
+    RecordSafepointWithRegisters(
+        instr->pointer_map(), 0, Safepoint::kNoLazyDeopt);
+    __ StoreToSafepointRegisterSlot(temp_result, eax);
+  }
+  X87PrepareToWrite(result_reg);
+  // return value of MathExpRT is Smi or Heap Number.
+  __ JumpIfSmi(temp_result, &smi);
+  // Heap number(double)
+  __ fld_d(FieldOperand(temp_result, HeapNumber::kValueOffset));
+  __ jmp(&finish);
+  // SMI
+  __ bind(&smi);
+  __ SmiUntag(temp_result);
+  __ push(temp_result);
+  __ fild_s(MemOperand(esp, 0));
+  __ pop(temp_result);
+  __ bind(&finish);
+  X87CommitWrite(result_reg);
 }
 
 

src/x87/lithium-x87.cc

@@ -1252,8 +1252,10 @@ LInstruction* LChunkBuilder::DoMathExp(HUnaryMathOperation* instr) {
 
 LInstruction* LChunkBuilder::DoMathSqrt(HUnaryMathOperation* instr) {
   LOperand* input = UseRegisterAtStart(instr->value());
-  LMathSqrt* result = new(zone()) LMathSqrt(input);
-  return DefineSameAsFirst(result);
+  LOperand* temp1 = FixedTemp(ecx);
+  LOperand* temp2 = FixedTemp(edx);
+  LMathSqrt* result = new(zone()) LMathSqrt(input, temp1, temp2);
+  return MarkAsCall(DefineSameAsFirst(result), instr);
 }
 
 

src/x87/lithium-x87.h

@@ -973,13 +973,19 @@ class LMathExp FINAL : public LTemplateInstruction<1, 1, 2> {
 };
 
 
-class LMathSqrt FINAL : public LTemplateInstruction<1, 1, 0> {
+class LMathSqrt FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
-  explicit LMathSqrt(LOperand* value) {
+  explicit LMathSqrt(LOperand* value,
+                     LOperand* temp1,
+                     LOperand* temp2) {
     inputs_[0] = value;
+    temps_[0] = temp1;
+    temps_[1] = temp2;
   }
 
   LOperand* value() { return inputs_[0]; }
+  LOperand* temp1() { return temps_[0]; }
+  LOperand* temp2() { return temps_[1]; }
 
   DECLARE_CONCRETE_INSTRUCTION(MathSqrt, "math-sqrt")
 };