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[arm] Improve generation of flag setting instructions.

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Generate a flag-setting instruction for a binary operation when
the result is tested for equality/inequality to zero.

BUG=

Review-Url: https://codereview.chromium.org/2315453002
Cr-Commit-Position: refs/heads/master@{#39183}
This commit is contained in:
georgia.kouveli 2016-09-05 09:18:00 -07:00 committed by Commit bot
parent 494e2493f2
commit 9da7ac6fdb
2 changed files with 13 additions and 16 deletions
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4
src/compiler/arm/instruction-selector-arm.cc
View File

@ -1958,6 +1958,10 @@ void VisitWordCompareZero(InstructionSelector* selector, Node* user,
break;
}
if (user->opcode() == IrOpcode::kWord32Equal) {
return VisitWordCompare(selector, user, cont);
}
// Continuation could not be combined with a compare, emit compare against 0.
ArmOperandGenerator g(selector);
InstructionCode const opcode =

25
test/unittests/compiler/arm/instruction-selector-arm-unittest.cc
View File

@ -2079,10 +2079,6 @@ TEST_P(InstructionSelectorFlagSettingTest, CmpZeroOnlyUserInBasicBlock) {
const FlagSettingInst inst = GetParam();
// Binop with additional users, but in a different basic block.
TRACED_FOREACH(Comparison, cmp, kBinopCmpZeroRightInstructions) {
// We don't optimise this case at the moment.
if (cmp.flags_condition == kEqual || cmp.flags_condition == kNotEqual) {
continue;
}
StreamBuilder m(this, MachineType::Int32(), MachineType::Int32(),
MachineType::Int32());
RawMachineLabel a, b;
@ -2108,10 +2104,6 @@ TEST_P(InstructionSelectorFlagSettingTest, ShiftedOperand) {
const FlagSettingInst inst = GetParam();
// Like the test above, but with a shifted input to the binary operator.
TRACED_FOREACH(Comparison, cmp, kBinopCmpZeroRightInstructions) {
// We don't optimise this case at the moment.
if (cmp.flags_condition == kEqual || cmp.flags_condition == kNotEqual) {
continue;
}
StreamBuilder m(this, MachineType::Int32(), MachineType::Int32(),
MachineType::Int32());
RawMachineLabel a, b;
@ -2158,8 +2150,7 @@ TEST_P(InstructionSelectorFlagSettingTest, UsersInSameBasicBlock) {
EXPECT_EQ(inst.arch_opcode, s[0]->arch_opcode());
EXPECT_NE(kFlags_branch, s[0]->flags_mode());
EXPECT_EQ(kArmMul, s[1]->arch_opcode());
EXPECT_EQ(cmp.flags_condition == kEqual ? kArmTst : kArmCmp,
s[2]->arch_opcode());
EXPECT_EQ(kArmCmp, s[2]->arch_opcode());
EXPECT_EQ(kFlags_branch, s[2]->flags_mode());
EXPECT_EQ(cmp.flags_condition, s[2]->flags_condition());
}
@ -3059,10 +3050,11 @@ TEST_F(InstructionSelectorTest, Word32EqualWithZero) {
m.Return(m.Word32Equal(m.Parameter(0), m.Int32Constant(0)));
Stream s = m.Build();
ASSERT_EQ(1U, s.size());
EXPECT_EQ(kArmTst, s[0]->arch_opcode());
EXPECT_EQ(kMode_Operand2_R, s[0]->addressing_mode());
EXPECT_EQ(kArmCmp, s[0]->arch_opcode());
EXPECT_EQ(kMode_Operand2_I, s[0]->addressing_mode());
ASSERT_EQ(2U, s[0]->InputCount());
EXPECT_EQ(s.ToVreg(s[0]->InputAt(0)), s.ToVreg(s[0]->InputAt(1)));
EXPECT_EQ(s.ToVreg(m.Parameter(0)), s.ToVreg(s[0]->InputAt(0)));
EXPECT_EQ(0, s.ToInt32(s[0]->InputAt(1)));
EXPECT_EQ(1U, s[0]->OutputCount());
EXPECT_EQ(kFlags_set, s[0]->flags_mode());
EXPECT_EQ(kEqual, s[0]->flags_condition());
@ -3072,10 +3064,11 @@ TEST_F(InstructionSelectorTest, Word32EqualWithZero) {
m.Return(m.Word32Equal(m.Int32Constant(0), m.Parameter(0)));
Stream s = m.Build();
ASSERT_EQ(1U, s.size());
EXPECT_EQ(kArmTst, s[0]->arch_opcode());
EXPECT_EQ(kMode_Operand2_R, s[0]->addressing_mode());
EXPECT_EQ(kArmCmp, s[0]->arch_opcode());
EXPECT_EQ(kMode_Operand2_I, s[0]->addressing_mode());
ASSERT_EQ(2U, s[0]->InputCount());
EXPECT_EQ(s.ToVreg(s[0]->InputAt(0)), s.ToVreg(s[0]->InputAt(1)));
EXPECT_EQ(s.ToVreg(m.Parameter(0)), s.ToVreg(s[0]->InputAt(0)));
EXPECT_EQ(0, s.ToInt32(s[0]->InputAt(1)));
EXPECT_EQ(1U, s[0]->OutputCount());
EXPECT_EQ(kFlags_set, s[0]->flags_mode());
EXPECT_EQ(kEqual, s[0]->flags_condition());