Handle non-constant divisor in MathFloorOfDiv, on ia32/x64

src/ia32/lithium-codegen-ia32.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 1194 matching lines @@
 
     __ bind(&remainder_eq_dividend);
     __ mov(result_reg, left_reg);
 
     __ bind(&done);
   }
 }
 
 
 void LCodeGen::DoDivI(LDivI* instr) {
-  if (instr->hydrogen()->HasPowerOf2Divisor()) {
+  if (!instr->is_flooring() && instr->hydrogen()->HasPowerOf2Divisor()) {
     Register dividend = ToRegister(instr->left());
     int32_t divisor =
         HConstant::cast(instr->hydrogen()->right())->Integer32Value();
     int32_t test_value = 0;
     int32_t power = 0;
 
     if (divisor > 0) {
       test_value = divisor - 1;
       power = WhichPowerOf2(divisor);
     } else {
@@ skipping 26 matching lines @@
   LOperand* right = instr->right();
   ASSERT(ToRegister(instr->result()).is(eax));
   ASSERT(ToRegister(instr->left()).is(eax));
   ASSERT(!ToRegister(instr->right()).is(eax));
   ASSERT(!ToRegister(instr->right()).is(edx));
 
   Register left_reg = eax;
 
   // Check for x / 0.
   Register right_reg = ToRegister(right);
-  if (instr->hydrogen()->CheckFlag(HValue::kCanBeDivByZero)) {
+  if (instr->hydrogen_value()->CheckFlag(HValue::kCanBeDivByZero)) {
     __ test(right_reg, ToOperand(right));
     DeoptimizeIf(zero, instr->environment());
   }
 
   // Check for (0 / -x) that will produce negative zero.
-  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
+  if (instr->hydrogen_value()->CheckFlag(HValue::kBailoutOnMinusZero)) {
     Label left_not_zero;
     __ test(left_reg, Operand(left_reg));
     __ j(not_zero, &left_not_zero, Label::kNear);
     __ test(right_reg, ToOperand(right));
     DeoptimizeIf(sign, instr->environment());
     __ bind(&left_not_zero);
   }
 
   // Check for (kMinInt / -1).
-  if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
+  if (instr->hydrogen_value()->CheckFlag(HValue::kCanOverflow)) {
     Label left_not_min_int;
     __ cmp(left_reg, kMinInt);
     __ j(not_zero, &left_not_min_int, Label::kNear);
     __ cmp(right_reg, -1);
     DeoptimizeIf(zero, instr->environment());
     __ bind(&left_not_min_int);
   }
 
   // Sign extend to edx.
   __ cdq();
   __ idiv(right_reg);
 
-  // Deoptimize if remainder is not 0.
-  __ test(edx, Operand(edx));
-  DeoptimizeIf(not_zero, instr->environment());
+  if (!instr->is_flooring()) {
+    // Deoptimize if remainder is not 0.
+    __ test(edx, Operand(edx));
+    DeoptimizeIf(not_zero, instr->environment());
+  } else {
+    Label done;

[Yang, 2012/12/27 14:41:53]

Tests, especially targetting this code path, would be really great. There are
many cases to test: positive/negative left and right, 0 in quotient and/or
remainder, etc.

+    __ test(edx, edx);
+    __ j(zero, &done, Label::kNear);
+    __ xor_(edx, right_reg);
+    __ sar(edx, 31);
+    __ add(eax, edx);
+    __ bind(&done);
+  }
 }
 
 
 void LCodeGen::DoMathFloorOfDiv(LMathFloorOfDiv* instr) {
   ASSERT(instr->right()->IsConstantOperand());
 
   Register dividend = ToRegister(instr->left());
   int32_t divisor = ToInteger32(LConstantOperand::cast(instr->right()));
   Register result = ToRegister(instr->result());
 
@@ skipping 4637 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32