[v8-dev] ARM: Improve double to integer truncation on ARM.

src/arm/lithium-codegen-arm.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 4708 matching lines @@
   STATIC_ASSERT(kHeapObjectTag == 1);
   __ adc(input_reg, input_reg, Operand(input_reg));
 
   // Heap number map check.
   __ ldr(scratch1, FieldMemOperand(input_reg, HeapObject::kMapOffset));
   __ LoadRoot(ip, Heap::kHeapNumberMapRootIndex);
   __ cmp(scratch1, Operand(ip));
 
   if (instr->truncating()) {
     Register scratch3 = ToRegister(instr->temp2());
-    SwVfpRegister single_scratch = double_scratch.low();
     ASSERT(!scratch3.is(input_reg) &&
            !scratch3.is(scratch1) &&
            !scratch3.is(scratch2));
     // Performs a truncating conversion of a floating point number as used by
     // the JS bitwise operations.
     Label heap_number;
     __ b(eq, &heap_number);
     // Check for undefined. Undefined is converted to zero for truncating
     // conversions.
     __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
     __ cmp(input_reg, Operand(ip));
     DeoptimizeIf(ne, instr->environment());
     __ mov(input_reg, Operand(0));
     __ b(&done);
 
     __ bind(&heap_number);
     __ sub(scratch1, input_reg, Operand(kHeapObjectTag));
     __ vldr(double_scratch2, scratch1, HeapNumber::kValueOffset);
 
     __ EmitECMATruncate(input_reg,
                         double_scratch2,
-                        single_scratch,
+                        double_scratch,
                         scratch1,
                         scratch2,
                         scratch3);
 
   } else {
     CpuFeatures::Scope scope(VFP3);
     // Deoptimize if we don't have a heap number.
     DeoptimizeIf(ne, instr->environment());
 
     __ sub(ip, input_reg, Operand(kHeapObjectTag));
@@ skipping 61 matching lines @@
                    instr->hydrogen()->deoptimize_on_minus_zero(),
                    instr->environment());
 }
 
 
 void LCodeGen::DoDoubleToI(LDoubleToI* instr) {
   Register result_reg = ToRegister(instr->result());
   Register scratch1 = scratch0();
   Register scratch2 = ToRegister(instr->temp());
   DwVfpRegister double_input = ToDoubleRegister(instr->value());
+  DwVfpRegister double_scratch = double_scratch0();
 
   Label done;
 
   if (instr->truncating()) {
     Register scratch3 = ToRegister(instr->temp2());
-    SwVfpRegister single_scratch = double_scratch0().low();
     __ EmitECMATruncate(result_reg,
                         double_input,
-                        single_scratch,
+                        double_scratch,
                         scratch1,
                         scratch2,
                         scratch3);
   } else {
-    DwVfpRegister double_scratch = double_scratch0();
     __ EmitVFPTruncate(kRoundToMinusInf,
                        result_reg,
                        double_input,
                        scratch1,
                        double_scratch,
                        kCheckForInexactConversion);
 
     // Deoptimize if we had a vfp invalid exception,
     // including inexact operation.
     DeoptimizeIf(ne, instr->environment());
@@ skipping 927 matching lines @@
   __ sub(scratch, result, Operand(index, LSL, kPointerSizeLog2 - kSmiTagSize));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal