[ia32] Match -0 - x with sign bit flip.

src/compiler/ia32/code-generator-ia32.cc

Index: src/compiler/ia32/code-generator-ia32.cc
diff --git a/src/compiler/ia32/code-generator-ia32.cc b/src/compiler/ia32/code-generator-ia32.cc
index 1d29372115d31c89dc482af74b297adbbf9776bc..19a76e075f5d077cbc2a0cde0cb129006b82fc61 100644
--- a/src/compiler/ia32/code-generator-ia32.cc
+++ b/src/compiler/ia32/code-generator-ia32.cc
@@ -18,6 +18,9 @@ namespace compiler {
 #define __ masm()->
 
 
+#define kScratchDoubleReg xmm0
+
+
 // Adds IA-32 specific methods for decoding operands.
 class IA32OperandConverter : public InstructionOperandConverter {
  public:
@@ -474,6 +477,14 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kSSEFloat32Sqrt:
       __ sqrtss(i.OutputDoubleRegister(), i.InputOperand(0));
       break;
+    case kSSEFloat32Neg: {
+      // TODO(bmeurer): Use 128-bit constants.
+      // TODO(turbofan): Add AVX version with relaxed register constraints.
+      __ pcmpeqd(kScratchDoubleReg, kScratchDoubleReg);
+      __ psllq(kScratchDoubleReg, 31);
+      __ xorps(i.OutputDoubleRegister(), kScratchDoubleReg);
+      break;
+    }
     case kSSEFloat64Cmp:
       __ ucomisd(i.InputDoubleRegister(0), i.InputOperand(1));
       break;
@@ -520,6 +531,14 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ add(esp, Immediate(kDoubleSize));
       break;
     }
+    case kSSEFloat64Neg: {
+      // TODO(bmeurer): Use 128-bit constants.
+      // TODO(turbofan): Add AVX version with relaxed register constraints.
+      __ pcmpeqd(kScratchDoubleReg, kScratchDoubleReg);
+      __ psllq(kScratchDoubleReg, 63);
+      __ xorpd(i.OutputDoubleRegister(), kScratchDoubleReg);
+      break;
+    }
     case kSSEFloat64Sqrt:
       __ sqrtsd(i.OutputDoubleRegister(), i.InputOperand(0));
       break;
@@ -540,10 +559,9 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ cvttsd2si(i.OutputRegister(), i.InputOperand(0));
       break;
     case kSSEFloat64ToUint32: {
-      XMMRegister scratch = xmm0;
-      __ Move(scratch, -2147483648.0);
-      __ addsd(scratch, i.InputOperand(0));
-      __ cvttsd2si(i.OutputRegister(), scratch);
+      __ Move(kScratchDoubleReg, -2147483648.0);
+      __ addsd(kScratchDoubleReg, i.InputOperand(0));
+      __ cvttsd2si(i.OutputRegister(), kScratchDoubleReg);
       __ add(i.OutputRegister(), Immediate(0x80000000));
       break;
     }
@@ -1303,10 +1321,9 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
       XMMRegister dst = g.ToDoubleRegister(destination);
       __ movsd(dst, src);
     } else {
-      // We rely on having xmm0 available as a fixed scratch register.
       Operand dst = g.ToOperand(destination);
-      __ movsd(xmm0, src);
-      __ movsd(dst, xmm0);
+      __ movsd(kScratchDoubleReg, src);
+      __ movsd(dst, kScratchDoubleReg);
     }
   } else {
     UNREACHABLE();
@@ -1336,33 +1353,31 @@ void CodeGenerator::AssembleSwap(InstructionOperand* source,
     __ pop(dst);
     __ pop(src);
   } else if (source->IsDoubleRegister() && destination->IsDoubleRegister()) {
-    // XMM register-register swap. We rely on having xmm0
-    // available as a fixed scratch register.
+    // XMM register-register swap.
     XMMRegister src = g.ToDoubleRegister(source);
     XMMRegister dst = g.ToDoubleRegister(destination);
-    __ movaps(xmm0, src);
+    __ movaps(kScratchDoubleReg, src);
     __ movaps(src, dst);
-    __ movaps(dst, xmm0);
+    __ movaps(dst, kScratchDoubleReg);
   } else if (source->IsDoubleRegister() && destination->IsDoubleStackSlot()) {
-    // XMM register-memory swap.  We rely on having xmm0
-    // available as a fixed scratch register.
+    // XMM register-memory swap.
     XMMRegister reg = g.ToDoubleRegister(source);
     Operand other = g.ToOperand(destination);
-    __ movsd(xmm0, other);
+    __ movsd(kScratchDoubleReg, other);
     __ movsd(other, reg);
-    __ movaps(reg, xmm0);
+    __ movaps(reg, kScratchDoubleReg);
   } else if (source->IsDoubleStackSlot() && destination->IsDoubleStackSlot()) {
     // Double-width memory-to-memory.
     Operand src0 = g.ToOperand(source);
     Operand src1 = g.HighOperand(source);
     Operand dst0 = g.ToOperand(destination);
     Operand dst1 = g.HighOperand(destination);
-    __ movsd(xmm0, dst0);  // Save destination in xmm0.
-    __ push(src0);         // Then use stack to copy source to destination.
+    __ movsd(kScratchDoubleReg, dst0);  // Save destination in scratch register.
+    __ push(src0);  // Then use stack to copy source to destination.
     __ pop(dst0);
     __ push(src1);
     __ pop(dst1);
-    __ movsd(src0, xmm0);
+    __ movsd(src0, kScratchDoubleReg);
   } else {
     // No other combinations are possible.
     UNREACHABLE();