Port r11517 (not deopt Math.floor on negative input) to x64, sse2.

src/x64/lithium-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3013 matching lines @@
     __ Integer32ToSmi(input_reg, input_reg);
     __ bind(deferred->exit());
   }
 }
 
 
 void LCodeGen::DoMathFloor(LUnaryMathOperation* instr) {
   XMMRegister xmm_scratch = xmm0;
   Register output_reg = ToRegister(instr->result());
   XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
-  Label done;
 
   if (CpuFeatures::IsSupported(SSE4_1)) {
     CpuFeatures::Scope scope(SSE4_1);
     if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
       // Deoptimize if minus zero.
       __ movq(output_reg, input_reg);
       __ subq(output_reg, Immediate(1));
       DeoptimizeIf(overflow, instr->environment());
     }
     __ roundsd(xmm_scratch, input_reg, Assembler::kRoundDown);
     __ cvttsd2si(output_reg, xmm_scratch);
     __ cmpl(output_reg, Immediate(0x80000000));
     DeoptimizeIf(equal, instr->environment());
   } else {
+    Label negative_sign, done;
     // Deoptimize on negative inputs.
     __ xorps(xmm_scratch, xmm_scratch);  // Zero the register.
     __ ucomisd(input_reg, xmm_scratch);
-    DeoptimizeIf(below, instr->environment());
+    DeoptimizeIf(parity_even, instr->environment());
+    __ j(below, &negative_sign, Label::kNear);
+
     if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
       // Check for negative zero.
       Label positive_sign;
       __ j(above, &positive_sign, Label::kNear);
       __ movmskpd(output_reg, input_reg);
       __ testq(output_reg, Immediate(1));
       DeoptimizeIf(not_zero, instr->environment());
       __ Set(output_reg, 0);
       __ jmp(&done);
       __ bind(&positive_sign);
     }
 
     // Use truncating instruction (OK because input is positive).
     __ cvttsd2si(output_reg, input_reg);
-
     // Overflow is signalled with minint.
     __ cmpl(output_reg, Immediate(0x80000000));
     DeoptimizeIf(equal, instr->environment());
+    __ jmp(&done, Label::kNear);
+
+    // Non-zero negative reaches here.
+    __ bind(&negative_sign);
+    // Truncate, then compare and compensate.
+    __ cvttsd2si(output_reg, input_reg);
+    __ cvtlsi2sd(xmm_scratch, output_reg);
+    __ ucomisd(input_reg, xmm_scratch);
+    __ j(equal, &done, Label::kNear);
+    __ subl(output_reg, Immediate(1));
+    DeoptimizeIf(overflow, instr->environment());
+
+    __ bind(&done);
   }
-  __ bind(&done);
 }
 
 
 void LCodeGen::DoMathRound(LUnaryMathOperation* instr) {
   const XMMRegister xmm_scratch = xmm0;
   Register output_reg = ToRegister(instr->result());
   XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
 
   Label done;
   // xmm_scratch = 0.5
@@ skipping 1952 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64