Revision: 11427
Author: [email protected]
Date: Tue Apr 24 08:59:07 2012
Log: Optimise Math.floor(x/y) to use integer division for specific
divisor.
Landing for Rodolph Perfetta <[email protected]>.
Original CL: http://codereview.chromium.org/9638018/
Review URL: https://chromiumcodereview.appspot.com/10197010
http://code.google.com/p/v8/source/detail?r=11427
Added:
/branches/bleeding_edge/test/mjsunit/math-floor-of-div.js
Modified:
/branches/bleeding_edge/src/arm/lithium-arm.cc
/branches/bleeding_edge/src/arm/lithium-arm.h
/branches/bleeding_edge/src/arm/lithium-codegen-arm.cc
/branches/bleeding_edge/src/arm/lithium-codegen-arm.h
/branches/bleeding_edge/src/arm/macro-assembler-arm.cc
/branches/bleeding_edge/src/arm/macro-assembler-arm.h
/branches/bleeding_edge/src/compiler-intrinsics.h
/branches/bleeding_edge/src/frames.cc
/branches/bleeding_edge/src/hydrogen-instructions.cc
/branches/bleeding_edge/src/hydrogen-instructions.h
/branches/bleeding_edge/src/ia32/lithium-ia32.cc
/branches/bleeding_edge/src/mips/lithium-mips.cc
/branches/bleeding_edge/src/utils.cc
/branches/bleeding_edge/src/utils.h
/branches/bleeding_edge/src/x64/lithium-x64.cc
=======================================
--- /dev/null
+++ /branches/bleeding_edge/test/mjsunit/math-floor-of-div.js Tue Apr 24
08:59:07 2012
@@ -0,0 +1,216 @@
+// 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
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --allow-natives-syntax --nouse_inlining
+
+// Use this function as reference. Make sure it is not inlined.
+function div(a, b) {
+ return a / b;
+}
+
+var limit = 0x1000000;
+var exhaustive_limit = 100;
+var step = 10;
+var values = [0x10000001,
+ 0x12345678,
+ -0x789abcdf, // 0x87654321
+ 0x01234567,
+ 0x76543210,
+ -0x80000000, // 0x80000000
+ 0x7fffffff,
+ -0x0fffffff, // 0xf0000001
+ 0x00000010,
+ -0x01000000 // 0xff000000
+ ];
+
+function test_div() {
+ var c = 0;
+ for (var k = 0; k <= limit; k++) {
+ if (k > exhaustive_limit) { c += step; k += c; }
+ assertEquals(Math.floor(div(k, 1)), Math.floor(k / 1));
+ assertEquals(Math.floor(div(k, -1)), Math.floor(k / -1));
+ assertEquals(Math.floor(div(k, 2)), Math.floor(k / 2));
+ assertEquals(Math.floor(div(k, -2)), Math.floor(k / -2));
+ assertEquals(Math.floor(div(k, 3)), Math.floor(k / 3));
+ assertEquals(Math.floor(div(k, -3)), Math.floor(k / -3));
+ assertEquals(Math.floor(div(k, 4)), Math.floor(k / 4));
+ assertEquals(Math.floor(div(k, -4)), Math.floor(k / -4));
+ assertEquals(Math.floor(div(k, 5)), Math.floor(k / 5));
+ assertEquals(Math.floor(div(k, -5)), Math.floor(k / -5));
+ assertEquals(Math.floor(div(k, 6)), Math.floor(k / 6));
+ assertEquals(Math.floor(div(k, -6)), Math.floor(k / -6));
+ assertEquals(Math.floor(div(k, 7)), Math.floor(k / 7));
+ assertEquals(Math.floor(div(k, -7)), Math.floor(k / -7));
+ assertEquals(Math.floor(div(k, 8)), Math.floor(k / 8));
+ assertEquals(Math.floor(div(k, -8)), Math.floor(k / -8));
+ assertEquals(Math.floor(div(k, 9)), Math.floor(k / 9));
+ assertEquals(Math.floor(div(k, -9)), Math.floor(k / -9));
+ assertEquals(Math.floor(div(k, 10)), Math.floor(k / 10));
+ assertEquals(Math.floor(div(k, -10)), Math.floor(k / -10));
+ assertEquals(Math.floor(div(k, 11)), Math.floor(k / 11));
+ assertEquals(Math.floor(div(k, -11)), Math.floor(k / -11));
+ assertEquals(Math.floor(div(k, 12)), Math.floor(k / 12));
+ assertEquals(Math.floor(div(k, -12)), Math.floor(k / -12));
+ assertEquals(Math.floor(div(k, 13)), Math.floor(k / 13));
+ assertEquals(Math.floor(div(k, -13)), Math.floor(k / -13));
+ assertEquals(Math.floor(div(k, 14)), Math.floor(k / 14));
+ assertEquals(Math.floor(div(k, -14)), Math.floor(k / -14));
+ assertEquals(Math.floor(div(k, 15)), Math.floor(k / 15));
+ assertEquals(Math.floor(div(k, -15)), Math.floor(k / -15));
+ assertEquals(Math.floor(div(k, 16)), Math.floor(k / 16));
+ assertEquals(Math.floor(div(k, -16)), Math.floor(k / -16));
+ assertEquals(Math.floor(div(k, 17)), Math.floor(k / 17));
+ assertEquals(Math.floor(div(k, -17)), Math.floor(k / -17));
+ assertEquals(Math.floor(div(k, 18)), Math.floor(k / 18));
+ assertEquals(Math.floor(div(k, -18)), Math.floor(k / -18));
+ assertEquals(Math.floor(div(k, 19)), Math.floor(k / 19));
+ assertEquals(Math.floor(div(k, -19)), Math.floor(k / -19));
+ assertEquals(Math.floor(div(k, 20)), Math.floor(k / 20));
+ assertEquals(Math.floor(div(k, -20)), Math.floor(k / -20));
+ assertEquals(Math.floor(div(k, 21)), Math.floor(k / 21));
+ assertEquals(Math.floor(div(k, -21)), Math.floor(k / -21));
+ assertEquals(Math.floor(div(k, 22)), Math.floor(k / 22));
+ assertEquals(Math.floor(div(k, -22)), Math.floor(k / -22));
+ assertEquals(Math.floor(div(k, 23)), Math.floor(k / 23));
+ assertEquals(Math.floor(div(k, -23)), Math.floor(k / -23));
+ assertEquals(Math.floor(div(k, 24)), Math.floor(k / 24));
+ assertEquals(Math.floor(div(k, -24)), Math.floor(k / -24));
+ assertEquals(Math.floor(div(k, 25)), Math.floor(k / 25));
+ assertEquals(Math.floor(div(k, -25)), Math.floor(k / -25));
+ assertEquals(Math.floor(div(k, 125)), Math.floor(k / 125));
+ assertEquals(Math.floor(div(k, -125)), Math.floor(k / -125));
+ assertEquals(Math.floor(div(k, 625)), Math.floor(k / 625));
+ assertEquals(Math.floor(div(k, -625)), Math.floor(k / -625));
+ }
+ c = 0;
+ for (var k = 0; k <= limit; k++) {
+ if (k > exhaustive_limit) { c += step; k += c; }
+ assertEquals(Math.floor(div(-k, 1)), Math.floor(-k / 1));
+ assertEquals(Math.floor(div(-k, -1)), Math.floor(-k / -1));
+ assertEquals(Math.floor(div(-k, 2)), Math.floor(-k / 2));
+ assertEquals(Math.floor(div(-k, -2)), Math.floor(-k / -2));
+ assertEquals(Math.floor(div(-k, 3)), Math.floor(-k / 3));
+ assertEquals(Math.floor(div(-k, -3)), Math.floor(-k / -3));
+ assertEquals(Math.floor(div(-k, 4)), Math.floor(-k / 4));
+ assertEquals(Math.floor(div(-k, -4)), Math.floor(-k / -4));
+ assertEquals(Math.floor(div(-k, 5)), Math.floor(-k / 5));
+ assertEquals(Math.floor(div(-k, -5)), Math.floor(-k / -5));
+ assertEquals(Math.floor(div(-k, 6)), Math.floor(-k / 6));
+ assertEquals(Math.floor(div(-k, -6)), Math.floor(-k / -6));
+ assertEquals(Math.floor(div(-k, 7)), Math.floor(-k / 7));
+ assertEquals(Math.floor(div(-k, -7)), Math.floor(-k / -7));
+ assertEquals(Math.floor(div(-k, 8)), Math.floor(-k / 8));
+ assertEquals(Math.floor(div(-k, -8)), Math.floor(-k / -8));
+ assertEquals(Math.floor(div(-k, 9)), Math.floor(-k / 9));
+ assertEquals(Math.floor(div(-k, -9)), Math.floor(-k / -9));
+ assertEquals(Math.floor(div(-k, 10)), Math.floor(-k / 10));
+ assertEquals(Math.floor(div(-k, -10)), Math.floor(-k / -10));
+ assertEquals(Math.floor(div(-k, 11)), Math.floor(-k / 11));
+ assertEquals(Math.floor(div(-k, -11)), Math.floor(-k / -11));
+ assertEquals(Math.floor(div(-k, 12)), Math.floor(-k / 12));
+ assertEquals(Math.floor(div(-k, -12)), Math.floor(-k / -12));
+ assertEquals(Math.floor(div(-k, 13)), Math.floor(-k / 13));
+ assertEquals(Math.floor(div(-k, -13)), Math.floor(-k / -13));
+ assertEquals(Math.floor(div(-k, 14)), Math.floor(-k / 14));
+ assertEquals(Math.floor(div(-k, -14)), Math.floor(-k / -14));
+ assertEquals(Math.floor(div(-k, 15)), Math.floor(-k / 15));
+ assertEquals(Math.floor(div(-k, -15)), Math.floor(-k / -15));
+ assertEquals(Math.floor(div(-k, 16)), Math.floor(-k / 16));
+ assertEquals(Math.floor(div(-k, -16)), Math.floor(-k / -16));
+ assertEquals(Math.floor(div(-k, 17)), Math.floor(-k / 17));
+ assertEquals(Math.floor(div(-k, -17)), Math.floor(-k / -17));
+ assertEquals(Math.floor(div(-k, 18)), Math.floor(-k / 18));
+ assertEquals(Math.floor(div(-k, -18)), Math.floor(-k / -18));
+ assertEquals(Math.floor(div(-k, 19)), Math.floor(-k / 19));
+ assertEquals(Math.floor(div(-k, -19)), Math.floor(-k / -19));
+ assertEquals(Math.floor(div(-k, 20)), Math.floor(-k / 20));
+ assertEquals(Math.floor(div(-k, -20)), Math.floor(-k / -20));
+ assertEquals(Math.floor(div(-k, 21)), Math.floor(-k / 21));
+ assertEquals(Math.floor(div(-k, -21)), Math.floor(-k / -21));
+ assertEquals(Math.floor(div(-k, 22)), Math.floor(-k / 22));
+ assertEquals(Math.floor(div(-k, -22)), Math.floor(-k / -22));
+ assertEquals(Math.floor(div(-k, 23)), Math.floor(-k / 23));
+ assertEquals(Math.floor(div(-k, -23)), Math.floor(-k / -23));
+ assertEquals(Math.floor(div(-k, 24)), Math.floor(-k / 24));
+ assertEquals(Math.floor(div(-k, -24)), Math.floor(-k / -24));
+ assertEquals(Math.floor(div(-k, 25)), Math.floor(-k / 25));
+ assertEquals(Math.floor(div(-k, -25)), Math.floor(-k / -25));
+ assertEquals(Math.floor(div(-k, 125)), Math.floor(-k / 125));
+ assertEquals(Math.floor(div(-k, -125)), Math.floor(-k / -125));
+ assertEquals(Math.floor(div(-k, 625)), Math.floor(-k / 625));
+ assertEquals(Math.floor(div(-k, -625)), Math.floor(-k / -625));
+ }
+ // Test for edge cases.
+ // Use (values[key] | 0) to force the integer type.
+ for (var i = 0; i < values.length; i++) {
+ for (var j = 0; j < values.length; j++) {
+ assertEquals(Math.floor(div((values[i] | 0), (values[j] | 0))),
+ Math.floor((values[i] | 0) / (values[j] | 0)));
+ assertEquals(Math.floor(div(-(values[i] | 0), (values[j] | 0))),
+ Math.floor(-(values[i] | 0) / (values[j] | 0)));
+ assertEquals(Math.floor(div((values[i] | 0), -(values[j] | 0))),
+ Math.floor((values[i] | 0) / -(values[j] | 0)));
+ assertEquals(Math.floor(div(-(values[i] | 0), -(values[j] | 0))),
+ Math.floor(-(values[i] | 0) / -(values[j] | 0)));
+ }
+ }
+}
+
+test_div();
+%OptimizeFunctionOnNextCall(test_div);
+test_div();
+
+// Test for negative zero and overflow.
+// Separate the tests to prevent deoptimizations from making the other
optimized
+// test unreachable.
+
+function IsNegativeZero(x) {
+ assertTrue(x == 0); // Is 0 or -0.
+ var y = 1 / x;
+ assertFalse(isFinite(y));
+ return y < 0;
+}
+
+function test_div_deopt_minus_zero() {
+ var zero_in_array = [0];
+ assertTrue(IsNegativeZero(Math.floor((zero_in_array[0] | 0) / -1)));
+}
+
+function test_div_deopt_overflow() {
+ // We box the value in an array to avoid constant propagation.
+ var min_int_in_array = [-2147483648];
+ // We use '| 0' to force the representation to int32.
+ assertEquals(-min_int_in_array[0],
+ Math.floor((min_int_in_array[0] | 0) / -1));
+}
+
+test_div_deopt_minus_zero();
+test_div_deopt_overflow();
+%OptimizeFunctionOnNextCall(test_div_deopt_minus_zero);
+%OptimizeFunctionOnNextCall(test_div_deopt_overflow);
+test_div_deopt_minus_zero();
+test_div_deopt_overflow();
=======================================
--- /branches/bleeding_edge/src/arm/lithium-arm.cc Mon Apr 23 11:12:36 2012
+++ /branches/bleeding_edge/src/arm/lithium-arm.cc Tue Apr 24 08:59:07 2012
@@ -1313,6 +1313,75 @@
return DoArithmeticT(Token::DIV, instr);
}
}
+
+
+bool LChunkBuilder::HasMagicNumberForDivisor(int32_t divisor) {
+ uint32_t divisor_abs = abs(divisor);
+ // Dividing by 0, 1, and powers of 2 is easy.
+ // Note that IsPowerOf2(0) returns true;
+ ASSERT(IsPowerOf2(0) == true);
+ if (IsPowerOf2(divisor_abs)) return true;
+
+ // We have magic numbers for a few specific divisors.
+ // Details and proofs can be found in:
+ // - Hacker's Delight, Henry S. Warren, Jr.
+ // - The PowerPC Compiler Writer’s Guide
+ // and probably many others.
+ //
+ // We handle
+ // <divisor with magic numbers> * <power of 2>
+ // but not
+ // <divisor with magic numbers> * <other divisor with magic numbers>
+ int32_t power_of_2_factor =
+ CompilerIntrinsics::CountTrailingZeros(divisor_abs);
+ DivMagicNumbers magic_numbers =
+ DivMagicNumberFor(divisor_abs >> power_of_2_factor);
+ if (magic_numbers.M != InvalidDivMagicNumber.M) return true;
+
+ return false;
+}
+
+
+HValue* LChunkBuilder::SimplifiedDividendForMathFloorOfDiv(HValue*
dividend) {
+ // A value with an integer representation does not need to be
transformed.
+ if (dividend->representation().IsInteger32()) {
+ return dividend;
+ // A change from an integer32 can be replaced by the integer32 value.
+ } else if (dividend->IsChange() &&
+ HChange::cast(dividend)->from().IsInteger32()) {
+ return HChange::cast(dividend)->value();
+ }
+ return NULL;
+}
+
+
+HValue* LChunkBuilder::SimplifiedDivisorForMathFloorOfDiv(HValue* divisor)
{
+ // Only optimize when we have magic numbers for the divisor.
+ // The standard integer division routine is usually slower than
transitionning
+ // to VFP.
+ if (divisor->IsConstant() &&
+ HConstant::cast(divisor)->HasInteger32Value()) {
+ HConstant* constant_val = HConstant::cast(divisor);
+ int32_t int32_val = constant_val->Integer32Value();
+ if (LChunkBuilder::HasMagicNumberForDivisor(int32_val)) {
+ return
constant_val->CopyToRepresentation(Representation::Integer32());
+ }
+ }
+ return NULL;
+}
+
+
+LInstruction* LChunkBuilder::DoMathFloorOfDiv(HMathFloorOfDiv* instr) {
+ HValue* right = instr->right();
+ LOperand* dividend = UseRegister(instr->left());
+ LOperand* divisor = UseRegisterOrConstant(right);
+ LOperand* remainder = TempRegister();
+ ASSERT(right->IsConstant() &&
+ HConstant::cast(right)->HasInteger32Value() &&
+
HasMagicNumberForDivisor(HConstant::cast(right)->Integer32Value()));
+ return AssignEnvironment(DefineAsRegister(
+ new LMathFloorOfDiv(dividend, divisor, remainder)));
+}
LInstruction* LChunkBuilder::DoMod(HMod* instr) {
=======================================
--- /branches/bleeding_edge/src/arm/lithium-arm.h Mon Apr 23 11:12:36 2012
+++ /branches/bleeding_edge/src/arm/lithium-arm.h Tue Apr 24 08:59:07 2012
@@ -132,6 +132,7 @@
V(LoadNamedField) \
V(LoadNamedFieldPolymorphic) \
V(LoadNamedGeneric) \
+ V(MathFloorOfDiv) \
V(ModI) \
V(MulI) \
V(NumberTagD) \
@@ -579,6 +580,21 @@
};
+class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
+ public:
+ LMathFloorOfDiv(LOperand* left,
+ LOperand* right,
+ LOperand* temp = NULL) {
+ inputs_[0] = left;
+ inputs_[1] = right;
+ temps_[0] = temp;
+ }
+
+ DECLARE_CONCRETE_INSTRUCTION(MathFloorOfDiv, "math-floor-of-div")
+ DECLARE_HYDROGEN_ACCESSOR(MathFloorOfDiv)
+};
+
+
class LMulI: public LTemplateInstruction<1, 2, 1> {
public:
LMulI(LOperand* left, LOperand* right, LOperand* temp) {
@@ -2287,6 +2303,10 @@
HYDROGEN_CONCRETE_INSTRUCTION_LIST(DECLARE_DO)
#undef DECLARE_DO
+ static bool HasMagicNumberForDivisor(int32_t divisor);
+ static HValue* SimplifiedDividendForMathFloorOfDiv(HValue* val);
+ static HValue* SimplifiedDivisorForMathFloorOfDiv(HValue* val);
+
private:
enum Status {
UNUSED,
=======================================
--- /branches/bleeding_edge/src/arm/lithium-codegen-arm.cc Mon Apr 23
11:12:36 2012
+++ /branches/bleeding_edge/src/arm/lithium-codegen-arm.cc Tue Apr 24
08:59:07 2012
@@ -1032,6 +1032,100 @@
__ bind(&done);
}
+
+
+void LCodeGen::EmitSignedIntegerDivisionByConstant(
+ Register result,
+ Register dividend,
+ int32_t divisor,
+ Register remainder,
+ Register scratch,
+ LEnvironment* environment) {
+ ASSERT(!AreAliased(dividend, scratch, ip));
+ ASSERT(LChunkBuilder::HasMagicNumberForDivisor(divisor));
+
+ uint32_t divisor_abs = abs(divisor);
+
+ int32_t power_of_2_factor =
+ CompilerIntrinsics::CountTrailingZeros(divisor_abs);
+
+ switch (divisor_abs) {
+ case 0:
+ DeoptimizeIf(al, environment);
+ return;
+
+ case 1:
+ if (divisor > 0) {
+ __ Move(result, dividend);
+ } else {
+ __ rsb(result, dividend, Operand(0), SetCC);
+ DeoptimizeIf(vs, environment);
+ }
+ // Compute the remainder.
+ __ mov(remainder, Operand(0));
+ return;
+
+ default:
+ if (IsPowerOf2(divisor_abs)) {
+ // Branch and condition free code for integer division by a power
+ // of two.
+ int32_t power = WhichPowerOf2(divisor_abs);
+ if (power > 1) {
+ __ mov(scratch, Operand(dividend, ASR, power - 1));
+ }
+ __ add(scratch, dividend, Operand(scratch, LSR, 32 - power));
+ __ mov(result, Operand(scratch, ASR, power));
+ // Negate if necessary.
+ // We don't need to check for overflow because the case '-1' is
+ // handled separately.
+ if (divisor < 0) {
+ ASSERT(divisor != -1);
+ __ rsb(result, result, Operand(0));
+ }
+ // Compute the remainder.
+ if (divisor > 0) {
+ __ sub(remainder, dividend, Operand(result, LSL, power));
+ } else {
+ __ add(remainder, dividend, Operand(result, LSL, power));
+ }
+ return;
+ } else {
+ // Use magic numbers for a few specific divisors.
+ // Details and proofs can be found in:
+ // - Hacker's Delight, Henry S. Warren, Jr.
+ // - The PowerPC Compiler Writer’s Guide
+ // and probably many others.
+ //
+ // We handle
+ // <divisor with magic numbers> * <power of 2>
+ // but not
+ // <divisor with magic numbers> * <other divisor with magic
numbers>
+ DivMagicNumbers magic_numbers =
+ DivMagicNumberFor(divisor_abs >> power_of_2_factor);
+ // Branch and condition free code for integer division by a power
+ // of two.
+ const int32_t M = magic_numbers.M;
+ const int32_t s = magic_numbers.s + power_of_2_factor;
+
+ __ mov(ip, Operand(M));
+ __ smull(ip, scratch, dividend, ip);
+ if (M < 0) {
+ __ add(scratch, scratch, Operand(dividend));
+ }
+ if (s > 0) {
+ __ mov(scratch, Operand(scratch, ASR, s));
+ }
+ __ add(result, scratch, Operand(dividend, LSR, 31));
+ if (divisor < 0) __ rsb(result, result, Operand(0));
+ // Compute the remainder.
+ __ mov(ip, Operand(divisor));
+ // This sequence could be replaced with 'mls' when
+ // it gets implemented.
+ __ mul(scratch, result, ip);
+ __ sub(remainder, dividend, scratch);
+ }
+ }
+}
void LCodeGen::DoDivI(LDivI* instr) {
@@ -1113,6 +1207,34 @@
DeoptimizeIf(al, instr->environment());
__ bind(&done);
}
+
+
+void LCodeGen::DoMathFloorOfDiv(LMathFloorOfDiv* instr) {
+ const Register result = ToRegister(instr->result());
+ const Register left = ToRegister(instr->InputAt(0));
+ const Register remainder = ToRegister(instr->TempAt(0));
+ const Register scratch = scratch0();
+
+ // We only optimize this for division by constants, because the standard
+ // integer division routine is usually slower than transitionning to VFP.
+ // This could be optimized on processors with SDIV available.
+ ASSERT(instr->InputAt(1)->IsConstantOperand());
+ int32_t divisor = ToInteger32(LConstantOperand::cast(instr->InputAt(1)));
+ if (divisor < 0) {
+ __ cmp(left, Operand(0));
+ DeoptimizeIf(eq, instr->environment());
+ }
+ EmitSignedIntegerDivisionByConstant(result,
+ left,
+ divisor,
+ remainder,
+ scratch,
+ instr->environment());
+ // We operated a truncating division. Correct the result if necessary.
+ __ cmp(remainder, Operand(0));
+ __ teq(remainder, Operand(divisor), ne);
+ __ sub(result, result, Operand(1), LeaveCC, mi);
+}
template<int T>
=======================================
--- /branches/bleeding_edge/src/arm/lithium-codegen-arm.h Mon Apr 23
11:12:36 2012
+++ /branches/bleeding_edge/src/arm/lithium-codegen-arm.h Tue Apr 24
08:59:07 2012
@@ -323,6 +323,17 @@
Register source,
int* offset);
+ // Emit optimized code for integer division.
+ // Inputs are signed.
+ // All registers are clobbered.
+ // If 'remainder' is no_reg, it is not computed.
+ void EmitSignedIntegerDivisionByConstant(Register result,
+ Register dividend,
+ int32_t divisor,
+ Register remainder,
+ Register scratch,
+ LEnvironment* environment);
+
struct JumpTableEntry {
explicit inline JumpTableEntry(Address entry)
: label(),
=======================================
--- /branches/bleeding_edge/src/arm/macro-assembler-arm.cc Mon Apr 23
11:12:36 2012
+++ /branches/bleeding_edge/src/arm/macro-assembler-arm.cc Tue Apr 24
08:59:07 2012
@@ -3710,15 +3710,28 @@
}
-bool AreAliased(Register r1, Register r2, Register r3, Register r4) {
- if (r1.is(r2)) return true;
- if (r1.is(r3)) return true;
- if (r1.is(r4)) return true;
- if (r2.is(r3)) return true;
- if (r2.is(r4)) return true;
- if (r3.is(r4)) return true;
- return false;
-}
+#ifdef DEBUG
+bool AreAliased(Register reg1,
+ Register reg2,
+ Register reg3,
+ Register reg4,
+ Register reg5,
+ Register reg6) {
+ int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() +
+ reg3.is_valid() + reg4.is_valid() + reg5.is_valid() + reg6.is_valid();
+
+ RegList regs = 0;
+ if (reg1.is_valid()) regs |= reg1.bit();
+ if (reg2.is_valid()) regs |= reg2.bit();
+ if (reg3.is_valid()) regs |= reg3.bit();
+ if (reg4.is_valid()) regs |= reg4.bit();
+ if (reg5.is_valid()) regs |= reg5.bit();
+ if (reg6.is_valid()) regs |= reg6.bit();
+ int n_of_non_aliasing_regs = NumRegs(regs);
+
+ return n_of_valid_regs != n_of_non_aliasing_regs;
+}
+#endif
CodePatcher::CodePatcher(byte* address, int instructions)
=======================================
--- /branches/bleeding_edge/src/arm/macro-assembler-arm.h Mon Apr 23
11:12:36 2012
+++ /branches/bleeding_edge/src/arm/macro-assembler-arm.h Tue Apr 24
08:59:07 2012
@@ -85,7 +85,14 @@
enum LinkRegisterStatus { kLRHasNotBeenSaved, kLRHasBeenSaved };
-bool AreAliased(Register r1, Register r2, Register r3, Register r4);
+#ifdef DEBUG
+bool AreAliased(Register reg1,
+ Register reg2,
+ Register reg3 = no_reg,
+ Register reg4 = no_reg,
+ Register reg5 = no_reg,
+ Register reg6 = no_reg);
+#endif
// MacroAssembler implements a collection of frequently used macros.
=======================================
--- /branches/bleeding_edge/src/compiler-intrinsics.h Mon Apr 23 11:12:36
2012
+++ /branches/bleeding_edge/src/compiler-intrinsics.h Tue Apr 24 08:59:07
2012
@@ -40,6 +40,9 @@
// Returns number of zero bits following most significant 1 bit.
// Undefined for zero value.
INLINE(static int CountLeadingZeros(uint32_t value));
+
+ // Returns the number of bits set.
+ INLINE(static int CountSetBits(uint32_t value));
};
#ifdef __GNUC__
@@ -50,6 +53,10 @@
int CompilerIntrinsics::CountLeadingZeros(uint32_t value) {
return __builtin_clz(value);
}
+
+int CompilerIntrinsics::CountSetBits(uint32_t value) {
+ return __builtin_popcount(value);
+}
#elif defined(_MSC_VER)
@@ -67,6 +74,23 @@
_BitScanReverse(&result, static_cast<long>(value)); //NOLINT
return 31 - static_cast<int>(result);
}
+
+int CompilerIntrinsics::CountSetBits(uint32_t value) {
+ // __popcnt is only supported from VS2008.
+#define _MSC_VER_VS2008 1500
+#if _MSC_VER >= _MSC_VER_VS2008
+ return __popcnt(value);
+#else
+ // Manually count set bits.
+ value = ((value >> 1) & 0x55555555) + (value & 0x55555555);
+ value = ((value >> 2) & 0x33333333) + (value & 0x33333333);
+ value = ((value >> 4) & 0x0f0f0f0f) + (value & 0x0f0f0f0f);
+ value = ((value >> 8) & 0x00ff00ff) + (value & 0x00ff00ff);
+ value = ((value >> 16) & 0x0000ffff) + (value & 0x0000ffff);
+ return value;
+#endif
+#undef _MSC_VER_VS2008
+}
#else
#error Unsupported compiler
=======================================
--- /branches/bleeding_edge/src/frames.cc Mon Apr 23 11:12:36 2012
+++ /branches/bleeding_edge/src/frames.cc Tue Apr 24 08:59:07 2012
@@ -1359,12 +1359,7 @@
//
-------------------------------------------------------------------------
int NumRegs(RegList reglist) {
- int n = 0;
- while (reglist != 0) {
- n++;
- reglist &= reglist - 1; // clear one bit
- }
- return n;
+ return CompilerIntrinsics::CountSetBits(reglist);
}
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.cc Mon Apr 23
11:12:36 2012
+++ /branches/bleeding_edge/src/hydrogen-instructions.cc Tue Apr 24
08:59:07 2012
@@ -929,6 +929,62 @@
stream->Add(" ");
typecheck()->PrintNameTo(stream);
}
+
+
+HValue* HUnaryMathOperation::Canonicalize() {
+ if (op() == kMathFloor) {
+ // If the input is integer32 then we replace the floor instruction
+ // with its input. This happens before the representation changes are
+ // introduced.
+ if (value()->representation().IsInteger32()) return value();
+
+#ifdef V8_TARGET_ARCH_ARM
+ if (value()->IsDiv() && (value()->UseCount() == 1)) {
+ // TODO(2038): Implement this optimization for non ARM architectures.
+ HDiv* hdiv = HDiv::cast(value());
+ HValue* left = hdiv->left();
+ HValue* right = hdiv->right();
+ // Try to simplify left and right values of the division.
+ HValue* new_left =
+ LChunkBuilder::SimplifiedDividendForMathFloorOfDiv(left);
+ HValue* new_right =
+ LChunkBuilder::SimplifiedDivisorForMathFloorOfDiv(right);
+
+ // Return if left or right are not optimizable.
+ if ((new_left == NULL) || (new_right == NULL)) return this;
+
+ // Insert the new values in the graph.
+ if (new_left->IsInstruction() &&
+ !HInstruction::cast(new_left)->IsLinked()) {
+ HInstruction::cast(new_left)->InsertBefore(this);
+ }
+ if (new_right->IsInstruction() &&
+ !HInstruction::cast(new_right)->IsLinked()) {
+ HInstruction::cast(new_right)->InsertBefore(this);
+ }
+ HMathFloorOfDiv* instr = new HMathFloorOfDiv(context(),
+ new_left,
+ new_right);
+ // Replace this HMathFloor instruction by the new HMathFloorOfDiv.
+ instr->InsertBefore(this);
+ ReplaceAllUsesWith(instr);
+ Kill();
+ // We know the division had no other uses than this HMathFloor.
Delete it.
+ // Also delete the arguments of the division if they are not used any
+ // more.
+ hdiv->DeleteAndReplaceWith(NULL);
+ ASSERT(left->IsChange() || left->IsConstant());
+ ASSERT(right->IsChange() || right->IsConstant());
+ if (left->HasNoUses()) left->DeleteAndReplaceWith(NULL);
+ if (right->HasNoUses()) right->DeleteAndReplaceWith(NULL);
+
+ // Return NULL to remove this instruction from the graph.
+ return NULL;
+ }
+#endif // V8_TARGET_ARCH_ARM
+ }
+ return this;
+}
HValue* HCheckInstanceType::Canonicalize() {
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.h Mon Apr 23 11:12:36
2012
+++ /branches/bleeding_edge/src/hydrogen-instructions.h Tue Apr 24 08:59:07
2012
@@ -140,6 +140,7 @@
V(LoadNamedField) \
V(LoadNamedFieldPolymorphic) \
V(LoadNamedGeneric) \
+ V(MathFloorOfDiv) \
V(Mod) \
V(Mul) \
V(ObjectLiteral) \
@@ -1992,15 +1993,7 @@
}
}
- virtual HValue* Canonicalize() {
- // If the input is integer32 then we replace the floor instruction
- // with its inputs. This happens before the representation changes are
- // introduced.
- if (op() == kMathFloor) {
- if (value()->representation().IsInteger32()) return value();
- }
- return this;
- }
+ virtual HValue* Canonicalize();
BuiltinFunctionId op() const { return op_; }
const char* OpName() const;
@@ -2758,6 +2751,25 @@
};
+class HMathFloorOfDiv: public HBinaryOperation {
+ public:
+ HMathFloorOfDiv(HValue* context, HValue* left, HValue* right)
+ : HBinaryOperation(context, left, right) {
+ set_representation(Representation::Integer32());
+ SetFlag(kUseGVN);
+ }
+
+ virtual Representation RequiredInputRepresentation(int index) {
+ return Representation::Integer32();
+ }
+
+ DECLARE_CONCRETE_INSTRUCTION(MathFloorOfDiv)
+
+ protected:
+ virtual bool DataEquals(HValue* other) { return true; }
+};
+
+
class HArithmeticBinaryOperation: public HBinaryOperation {
public:
HArithmeticBinaryOperation(HValue* context, HValue* left, HValue* right)
=======================================
--- /branches/bleeding_edge/src/ia32/lithium-ia32.cc Mon Apr 23 11:12:36
2012
+++ /branches/bleeding_edge/src/ia32/lithium-ia32.cc Tue Apr 24 08:59:07
2012
@@ -1353,6 +1353,12 @@
return DoArithmeticT(Token::DIV, instr);
}
}
+
+
+LInstruction* LChunkBuilder::DoMathFloorOfDiv(HMathFloorOfDiv* instr) {
+ UNIMPLEMENTED();
+ return NULL;
+}
LInstruction* LChunkBuilder::DoMod(HMod* instr) {
=======================================
--- /branches/bleeding_edge/src/mips/lithium-mips.cc Mon Apr 23 11:12:36
2012
+++ /branches/bleeding_edge/src/mips/lithium-mips.cc Tue Apr 24 08:59:07
2012
@@ -1314,6 +1314,12 @@
return DoArithmeticT(Token::DIV, instr);
}
}
+
+
+LInstruction* LChunkBuilder::DoMathFloorOfDiv(HMathFloorOfDiv* instr) {
+ UNIMPLEMENTED();
+ return NULL;
+}
LInstruction* LChunkBuilder::DoMod(HMod* instr) {
=======================================
--- /branches/bleeding_edge/src/utils.cc Mon Apr 23 11:12:36 2012
+++ /branches/bleeding_edge/src/utils.cc Tue Apr 24 08:59:07 2012
@@ -88,5 +88,20 @@
ASSERT(is_finalized());
return buffer_.start();
}
+
+
+const DivMagicNumbers DivMagicNumberFor(int32_t divisor) {
+ switch (divisor) {
+ case 3: return DivMagicNumberFor3;
+ case 5: return DivMagicNumberFor5;
+ case 7: return DivMagicNumberFor7;
+ case 9: return DivMagicNumberFor9;
+ case 11: return DivMagicNumberFor11;
+ case 25: return DivMagicNumberFor25;
+ case 125: return DivMagicNumberFor125;
+ case 625: return DivMagicNumberFor625;
+ default: return InvalidDivMagicNumber;
+ }
+}
} } // namespace v8::internal
=======================================
--- /branches/bleeding_edge/src/utils.h Mon Apr 23 11:12:36 2012
+++ /branches/bleeding_edge/src/utils.h Tue Apr 24 08:59:07 2012
@@ -83,6 +83,32 @@
return bits;
return 0;
}
+
+
+// Magic numbers for integer division.
+// These are kind of 2's complement reciprocal of the divisors.
+// Details and proofs can be found in:
+// - Hacker's Delight, Henry S. Warren, Jr.
+// - The PowerPC Compiler Writer’s Guide
+// and probably many others.
+// See details in the implementation of the algorithm in
+// lithium-codegen-arm.cc :
LCodeGen::TryEmitSignedIntegerDivisionByConstant().
+struct DivMagicNumbers {
+ unsigned M;
+ unsigned s;
+};
+
+const DivMagicNumbers InvalidDivMagicNumber= {0, 0};
+const DivMagicNumbers DivMagicNumberFor3 = {0x55555556, 0};
+const DivMagicNumbers DivMagicNumberFor5 = {0x66666667, 1};
+const DivMagicNumbers DivMagicNumberFor7 = {0x92492493, 2};
+const DivMagicNumbers DivMagicNumberFor9 = {0x38e38e39, 1};
+const DivMagicNumbers DivMagicNumberFor11 = {0x2e8ba2e9, 1};
+const DivMagicNumbers DivMagicNumberFor25 = {0x51eb851f, 3};
+const DivMagicNumbers DivMagicNumberFor125 = {0x10624dd3, 3};
+const DivMagicNumbers DivMagicNumberFor625 = {0x68db8bad, 8};
+
+const DivMagicNumbers DivMagicNumberFor(int32_t divisor);
// The C++ standard leaves the semantics of '>>' undefined for
=======================================
--- /branches/bleeding_edge/src/x64/lithium-x64.cc Mon Apr 23 11:12:36 2012
+++ /branches/bleeding_edge/src/x64/lithium-x64.cc Tue Apr 24 08:59:07 2012
@@ -1303,6 +1303,12 @@
return DoArithmeticT(Token::DIV, instr);
}
}
+
+
+LInstruction* LChunkBuilder::DoMathFloorOfDiv(HMathFloorOfDiv* instr) {
+ UNIMPLEMENTED();
+ return NULL;
+}
LInstruction* LChunkBuilder::DoMod(HMod* instr) {
--
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