Bring back the fisttp instruction on machines with SSE3, but check the

input so we don't have to check the exception flags afterwards.
Review URL: http://codereview.chromium.org/509001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3504 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/assembler-ia32.cc

@@ -1675,6 +1675,15 @@ void Assembler::fisttp_s(const Operand& adr) {
 }
 
 
+void Assembler::fisttp_d(const Operand& adr) {
+  ASSERT(CpuFeatures::IsEnabled(SSE3));
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0xDD);
+  emit_operand(ecx, adr);
+}
+
+
 void Assembler::fist_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;

src/ia32/assembler-ia32.h

@@ -693,6 +693,7 @@ class Assembler : public Malloced {
   void fistp_d(const Operand& adr);
 
   void fisttp_s(const Operand& adr);
+  void fisttp_d(const Operand& adr);
 
   void fabs();
   void fchs();

src/ia32/codegen-ia32.cc

@@ -764,6 +764,7 @@ class FloatingPointHelper : public AllStatic {
   // Takes the operands in edx and eax and loads them as integers in eax
   // and ecx.
   static void LoadAsIntegers(MacroAssembler* masm,
+                             bool use_sse3,
                              Label* operand_conversion_failure);
   // Test if operands are numbers (smi or HeapNumber objects), and load
   // them into xmm0 and xmm1 if they are.  Jump to label not_numbers if
@@ -7268,6 +7269,7 @@ void GenericBinaryOpStub::Generate(MacroAssembler* masm) {
       Label operand_conversion_failure;
       FloatingPointHelper::LoadAsIntegers(
         masm,
+        use_sse3_,
         &operand_conversion_failure);
       switch (op_) {
         case Token::BIT_OR:  __ or_(eax, Operand(ecx)); break;
@@ -7450,6 +7452,7 @@ void GenericBinaryOpStub::GenerateReturn(MacroAssembler* masm) {
 // trashed registers.
 void IntegerConvert(MacroAssembler* masm,
                     Register source,
+                    bool use_sse3,
                     Label* conversion_failure) {
   Label done, right_exponent, normal_exponent;
   Register scratch = ebx;
@@ -7459,6 +7462,22 @@ void IntegerConvert(MacroAssembler* masm,
   // Get exponent alone in scratch2.
   __ mov(scratch2, scratch);
   __ and_(scratch2, HeapNumber::kExponentMask);
+  if (use_sse3) {
+    CpuFeatures::Scope scope(SSE3);
+    // Check whether the exponent is too big for a 64 bit signed integer.
+    const uint32_t too_big_exponent =
+        (HeapNumber::kExponentBias + 63) << HeapNumber::kExponentShift;
+    __ cmp(Operand(scratch2), Immediate(too_big_exponent));
+    __ j(greater_equal, conversion_failure);
+    // Load x87 register with heap number.
+    __ fld_d(FieldOperand(source, HeapNumber::kValueOffset));
+    // Reserve space for 64 bit answer.
+    __ sub(Operand(esp), Immediate(sizeof(uint64_t)));  // Nolint.
+    // Do conversion, which cannot fail because we checked the exponent.
+    __ fisttp_d(Operand(esp, 0));
+    __ mov(ecx, Operand(esp, 0));  // Load low word of answer into ecx.
+    __ add(Operand(esp), Immediate(sizeof(uint64_t)));  // Nolint.
+  } else {
     // Load ecx with zero.  We use this either for the final shift or
     // for the answer.
     __ xor_(ecx, Operand(ecx));
@@ -7469,15 +7488,16 @@ void IntegerConvert(MacroAssembler* masm,
     const uint32_t non_smi_exponent =
         (HeapNumber::kExponentBias + 30) << HeapNumber::kExponentShift;
     __ cmp(Operand(scratch2), Immediate(non_smi_exponent));
-  // If we have a match of the int32-but-not-Smi exponent then skip some logic.
+    // If we have a match of the int32-but-not-Smi exponent then skip some
+    // logic.
     __ j(equal, &right_exponent);
     // If the exponent is higher than that then go to slow case.  This catches
     // numbers that don't fit in a signed int32, infinities and NaNs.
     __ j(less, &normal_exponent);
 
     {
-    // Handle a big exponent.  The only reason we have this code is that the >>>
-    // operator has a tendency to generate numbers with an exponent of 31.
+      // Handle a big exponent.  The only reason we have this code is that the
+      // >>> operator has a tendency to generate numbers with an exponent of 31.
       const uint32_t big_non_smi_exponent =
           (HeapNumber::kExponentBias + 31) << HeapNumber::kExponentShift;
       __ cmp(Operand(scratch2), Immediate(big_non_smi_exponent));
@@ -7539,8 +7559,8 @@ void IntegerConvert(MacroAssembler* masm,
     // actually need this because the bits get shifted out again, but
     // it's probably slower to test than just to do it.
     __ mov(scratch2, FieldOperand(source, HeapNumber::kMantissaOffset));
-  // Shift down 22 bits to get the most significant 10 bits or the low mantissa
-  // word.
+    // Shift down 22 bits to get the most significant 10 bits or the low
+    // mantissa word.
     __ shr(scratch2, 32 - shift_distance);
     __ or_(scratch2, Operand(scratch));
     // Move down according to the exponent.
@@ -7556,12 +7576,14 @@ void IntegerConvert(MacroAssembler* masm,
     __ bind(&negative);
     __ sub(ecx, Operand(scratch2));
     __ bind(&done);
+  }
 }
 
 
 // Input: edx, eax are the left and right objects of a bit op.
 // Output: eax, ecx are left and right integers for a bit op.
 void FloatingPointHelper::LoadAsIntegers(MacroAssembler* masm,
+                                         bool use_sse3,
                                          Label* conversion_failure) {
   // Check float operands.
   Label arg1_is_object, arg2_is_object, load_arg2;
@@ -7577,7 +7599,7 @@ void FloatingPointHelper::LoadAsIntegers(MacroAssembler* masm,
   __ cmp(ebx, Factory::heap_number_map());
   __ j(not_equal, conversion_failure);
   // Get the untagged integer version of the edx heap number in ecx.
-  IntegerConvert(masm, edx, conversion_failure);
+  IntegerConvert(masm, edx, use_sse3, conversion_failure);
   __ mov(edx, ecx);
 
   // Here edx has the untagged integer, eax has a Smi or a heap number.
@@ -7594,7 +7616,7 @@ void FloatingPointHelper::LoadAsIntegers(MacroAssembler* masm,
   __ cmp(ebx, Factory::heap_number_map());
   __ j(not_equal, conversion_failure);
   // Get the untagged integer version of the eax heap number in ecx.
-  IntegerConvert(masm, eax, conversion_failure);
+  IntegerConvert(masm, eax, use_sse3, conversion_failure);
   __ bind(&done);
   __ mov(eax, edx);
 }

test/mjsunit/smi-ops.js

@@ -638,6 +638,31 @@ function testShiftNonSmis() {
 
 testShiftNonSmis();
 
+function intConversion() {
+  function foo(x) {
+    assertEquals(x, (x * 1.0000000001) | 0, "foo more " + x);
+    assertEquals(x, x | 0, "foo " + x);
+    if (x > 0) {
+      assertEquals(x - 1, (x * 0.9999999999) | 0, "foo less " + x);
+    } else {
+      assertEquals(x + 1, (x * 0.9999999999) | 0, "foo less " + x);
+    }
+  }
+  for (var i = 1; i < 0x80000000; i *= 2) {
+    foo(i);
+    foo(-i);
+  }
+  for (var i = 1; i < 1/0; i *= 2) {
+    assertEquals(i | 0, (i * 1.0000000000000001) | 0, "b" + i);
+    assertEquals(-i | 0, (i * -1.0000000000000001) | 0, "c" + i);
+  }
+  for (var i = 0.5; i > 0; i /= 2) {
+    assertEquals(0, i | 0, "d" + i);
+    assertEquals(0, -i | 0, "e" + i);
+  }
+}
+
+intConversion();
 
 // Verify that we handle the (optimized) corner case of shifting by
 // zero even for non-smis.