X64: Use roundsd for DoMathFloor.

src/x64/lithium-codegen-x64.cc

 // Copyright 2011 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 2680 matching lines @@
     EmitIntegerMathAbs(instr);
     __ 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));
-  __ xorpd(xmm_scratch, xmm_scratch);  // Zero the register.
-  __ ucomisd(input_reg, xmm_scratch);
 
-  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
-    DeoptimizeIf(below_equal, instr->environment());
+  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 {
-    DeoptimizeIf(below, instr->environment());
+    __ xorpd(xmm_scratch, xmm_scratch);  // Zero the register.
+    __ ucomisd(input_reg, xmm_scratch);
+
+    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
+      DeoptimizeIf(below_equal, instr->environment());
+    } else {
+      DeoptimizeIf(below, instr->environment());
+    }
+
+    // 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());
   }
-
-  // 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());
 }
 
 
 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 1280 matching lines @@
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64