Consistently use a separate Lithium instruction for flooring division.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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
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@@ skipping 1187 matching lines @@
   __ jmp(&done, Label::kNear);
   __ bind(&needs_adjustment);
   __ leal(temp, Operand(dividend, divisor > 0 ? 1 : -1));
   __ TruncatingDiv(temp, Abs(divisor));
   if (divisor < 0) __ negl(rdx);
   __ decl(rdx);
   __ bind(&done);
 }
 
 
+// TODO(svenpanne) Refactor this to avoid code duplication with DoDivI.
+void LCodeGen::DoFlooringDivI(LFlooringDivI* instr) {
+  HBinaryOperation* hdiv = instr->hydrogen();
+  Register dividend = ToRegister(instr->dividend());
+  Register divisor = ToRegister(instr->divisor());
+  Register remainder = ToRegister(instr->temp());
+  Register result = ToRegister(instr->result());
+  ASSERT(dividend.is(rax));
+  ASSERT(remainder.is(rdx));
+  ASSERT(result.is(rax));
+  ASSERT(!divisor.is(rax));
+  ASSERT(!divisor.is(rdx));
+
+  // Check for x / 0.
+  if (hdiv->CheckFlag(HValue::kCanBeDivByZero)) {
+    __ testl(divisor, divisor);
+    DeoptimizeIf(zero, instr->environment());
+  }
+
+  // Check for (0 / -x) that will produce negative zero.
+  if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero)) {
+    Label dividend_not_zero;
+    __ testl(dividend, dividend);
+    __ j(not_zero, &dividend_not_zero, Label::kNear);
+    __ testl(divisor, divisor);
+    DeoptimizeIf(sign, instr->environment());
+    __ bind(&dividend_not_zero);
+  }
+
+  // Check for (kMinInt / -1).
+  if (hdiv->CheckFlag(HValue::kCanOverflow)) {
+    Label dividend_not_min_int;
+    __ cmpl(dividend, Immediate(kMinInt));
+    __ j(not_zero, &dividend_not_min_int, Label::kNear);
+    __ cmpl(divisor, Immediate(-1));
+    DeoptimizeIf(zero, instr->environment());
+    __ bind(&dividend_not_min_int);
+  }
+
+  // Sign extend to rdx (= remainder).
+  __ cdq();
+  __ idivl(divisor);
+
+  Label done;
+  __ testl(remainder, remainder);
+  __ j(zero, &done, Label::kNear);
+  __ xorl(remainder, divisor);
+  __ sarl(remainder, Immediate(31));
+  __ addl(result, remainder);
+  __ bind(&done);
+}
+
+
 void LCodeGen::DoDivByPowerOf2I(LDivByPowerOf2I* instr) {
   Register dividend = ToRegister(instr->dividend());
   int32_t divisor = instr->divisor();
   Register result = ToRegister(instr->result());
   ASSERT(divisor == kMinInt || IsPowerOf2(Abs(divisor)));
   ASSERT(!result.is(dividend));
 
   // Check for (0 / -x) that will produce negative zero.
   HDiv* hdiv = instr->hydrogen();
   if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
@@ skipping 47 matching lines @@
 
   if (!hdiv->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)) {
     __ movl(rax, rdx);
     __ imull(rax, rax, Immediate(divisor));
     __ subl(rax, dividend);
     DeoptimizeIf(not_equal, instr->environment());
   }
 }
 
 
+// TODO(svenpanne) Refactor this to avoid code duplication with DoFlooringDivI.
 void LCodeGen::DoDivI(LDivI* instr) {
   HBinaryOperation* hdiv = instr->hydrogen();
-  Register dividend = ToRegister(instr->left());
-  Register divisor = ToRegister(instr->right());
+  Register dividend = ToRegister(instr->dividend());
+  Register divisor = ToRegister(instr->divisor());
   Register remainder = ToRegister(instr->temp());
   Register result = ToRegister(instr->result());
   ASSERT(dividend.is(rax));
   ASSERT(remainder.is(rdx));
   ASSERT(result.is(rax));
   ASSERT(!divisor.is(rax));
   ASSERT(!divisor.is(rdx));
 
   // Check for x / 0.
   if (hdiv->CheckFlag(HValue::kCanBeDivByZero)) {
@@ skipping 18 matching lines @@
     __ j(not_zero, &dividend_not_min_int, Label::kNear);
     __ cmpl(divisor, Immediate(-1));
     DeoptimizeIf(zero, instr->environment());
     __ bind(&dividend_not_min_int);
   }
 
   // Sign extend to rdx (= remainder).
   __ cdq();
   __ idivl(divisor);
 
-  if (hdiv->IsMathFloorOfDiv()) {
-    Label done;
-    __ testl(remainder, remainder);
-    __ j(zero, &done, Label::kNear);
-    __ xorl(remainder, divisor);
-    __ sarl(remainder, Immediate(31));
-    __ addl(result, remainder);
-    __ bind(&done);
-  } else if (!hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
+  if (!hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
     // Deoptimize if remainder is not 0.
     __ testl(remainder, remainder);
     DeoptimizeIf(not_zero, instr->environment());
   }
 }
 
 
 void LCodeGen::DoMulI(LMulI* instr) {
   Register left = ToRegister(instr->left());
   LOperand* right = instr->right();
@@ skipping 4297 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64