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Specialize mint shift code on arm for a constant shift amount.

Browse source 
R=zra@google.com

Review URL: https://codereview.chromium.org//401683003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@38355 260f80e4-7a28-3924-810f-c04153c831b5
This commit is contained in:
regis@google.com 2014-07-17 22:29:33 +00:00
parent ffe364c2b5
commit 9d77c9ea73
4 changed files with 123 additions and 59 deletions
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160
runtime/vm/intermediate_language_arm.cc
View file

@ -6143,13 +6143,12 @@ void BinaryMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
LocationSummary* ShiftMintOpInstr::MakeLocationSummary(Isolate* isolate,
bool opt) const {
const intptr_t kNumInputs = 2;
const intptr_t kNumTemps = 1;
const intptr_t kNumTemps = 0;
LocationSummary* summary = new(isolate) LocationSummary(
isolate, kNumInputs, kNumTemps, LocationSummary::kNoCall);
summary->set_in(0, Location::Pair(Location::RequiresRegister(),
Location::RequiresRegister()));
summary->set_in(1, Location::WritableRegister());
summary->set_temp(0, Location::RequiresRegister());
summary->set_in(1, Location::WritableRegisterOrSmiConstant(right()));
summary->set_out(0, Location::Pair(Location::RequiresRegister(),
Location::RequiresRegister()));
return summary;
@ -6168,66 +6167,123 @@ void ShiftMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
PairLocation* left_pair = locs()->in(0).AsPairLocation();
Register left_lo = left_pair->At(0).reg();
Register left_hi = left_pair->At(1).reg();
Register shift = locs()->in(1).reg();
PairLocation* out_pair = locs()->out(0).AsPairLocation();
Register out_lo = out_pair->At(0).reg();
Register out_hi = out_pair->At(1).reg();
Register temp = locs()->temp(0).reg();
Label* deopt = NULL;
if (CanDeoptimize()) {
deopt = compiler->AddDeoptStub(deopt_id(), ICData::kDeoptShiftMintOp);
}
__ mov(out_lo, Operand(left_lo));
__ mov(out_hi, Operand(left_hi));
// Untag shift count.
__ SmiUntag(shift);
// Deopt if shift is larger than 63 or less than 0.
if (has_shift_count_check()) {
__ CompareImmediate(shift, kMintShiftCountLimit);
__ b(deopt, HI);
}
switch (op_kind()) {
case Token::kSHR: {
__ cmp(shift, Operand(32));
__ mov(out_lo, Operand(out_hi), HI);
__ Asr(out_hi, out_hi, 31, HI);
__ sub(shift, shift, Operand(32), HI);
__ rsb(temp, shift, Operand(32));
__ mov(temp, Operand(out_hi, LSL, temp));
__ orr(out_lo, temp, Operand(out_lo, LSR, shift));
__ Asr(out_hi, out_hi, shift);
break;
if (locs()->in(1).IsConstant()) {
// Code for a constant shift amount.
ASSERT(locs()->in(1).constant().IsSmi());
const int32_t shift =
reinterpret_cast<int32_t>(locs()->in(1).constant().raw()) >> 1;
if ((shift < 0) || (shift > kMintShiftCountLimit)) {
__ b(deopt);
return;
} else if (shift == 0) {
// Nothing to do for zero shift amount.
__ mov(out_lo, Operand(left_lo));
__ mov(out_hi, Operand(left_hi));
return;
}
case Token::kSHL: {
__ rsbs(temp, shift, Operand(32));
__ sub(temp, shift, Operand(32), MI);
__ mov(out_hi, Operand(out_lo, LSL, temp), MI);
__ mov(out_hi, Operand(out_hi, LSL, shift), PL);
__ orr(out_hi, out_hi, Operand(out_lo, LSR, temp), PL);
__ mov(out_lo, Operand(out_lo, LSL, shift));
// Check for overflow.
if (can_overflow()) {
// Copy high word from output.
__ mov(temp, Operand(out_hi));
// Shift copy right.
__ Asr(temp, temp, shift);
// Compare with high word from input.
__ cmp(temp, Operand(left_hi));
// Overflow if they aren't equal.
__ b(deopt, NE);
switch (op_kind()) {
case Token::kSHR: {
if (shift < 32) {
__ Lsl(out_lo, left_hi, 32 - shift);
__ orr(out_lo, out_lo, Operand(left_lo, LSR, shift));
__ Asr(out_hi, left_hi, shift);
} else {
if (shift == 32) {
__ mov(out_lo, Operand(left_hi));
} else {
__ Asr(out_lo, left_hi, shift - 32);
}
__ Asr(out_hi, left_hi, 31);
}
break;
}
break;
case Token::kSHL: {
if (shift < 32) {
__ Lsr(out_hi, left_lo, 32 - shift);
__ orr(out_hi, out_hi, Operand(left_hi, LSL, shift));
__ Lsl(out_lo, left_lo, shift);
} else {
if (shift == 32) {
__ mov(out_hi, Operand(left_lo));
} else {
__ Lsl(out_hi, left_lo, shift - 32);
}
__ mov(out_lo, Operand(0));
}
// Check for overflow.
if (can_overflow()) {
// Compare high word from input with shifted high word from output.
if (shift > 31) {
__ cmp(left_hi, Operand(out_hi));
} else {
__ cmp(left_hi, Operand(out_hi, ASR, shift));
}
// Overflow if they aren't equal.
__ b(deopt, NE);
}
break;
}
default:
UNREACHABLE();
}
} else {
// Code for a variable shift amount.
Register shift = locs()->in(1).reg();
// Untag shift count.
__ SmiUntag(shift);
// Deopt if shift is larger than 63 or less than 0.
if (has_shift_count_check()) {
__ CompareImmediate(shift, kMintShiftCountLimit);
__ b(deopt, HI);
}
__ mov(out_lo, Operand(left_lo));
__ mov(out_hi, Operand(left_hi));
switch (op_kind()) {
case Token::kSHR: {
__ cmp(shift, Operand(32));
__ mov(out_lo, Operand(out_hi), HI);
__ Asr(out_hi, out_hi, 31, HI);
__ sub(shift, shift, Operand(32), HI);
__ rsb(IP, shift, Operand(32));
__ mov(IP, Operand(out_hi, LSL, IP));
__ orr(out_lo, IP, Operand(out_lo, LSR, shift));
__ Asr(out_hi, out_hi, shift);
break;
}
case Token::kSHL: {
__ rsbs(IP, shift, Operand(32));
__ sub(IP, shift, Operand(32), MI);
__ mov(out_hi, Operand(out_lo, LSL, IP), MI);
__ mov(out_hi, Operand(out_hi, LSL, shift), PL);
__ orr(out_hi, out_hi, Operand(out_lo, LSR, IP), PL);
__ mov(out_lo, Operand(out_lo, LSL, shift));
// Check for overflow.
if (can_overflow()) {
// Compare high word from input with shifted high word from output.
__ cmp(left_hi, Operand(out_hi, ASR, shift));
// Overflow if they aren't equal.
__ b(deopt, NE);
}
break;
}
default:
UNREACHABLE();
}
default:
UNREACHABLE();
break;
}
if (FLAG_throw_on_javascript_int_overflow) {

13
runtime/vm/intermediate_language_ia32.cc
View file

@ -6038,7 +6038,6 @@ void ShiftMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
}
default:
UNREACHABLE();
break;
}
} else {
// Code for a variable shift amount.
@ -6061,10 +6060,10 @@ void ShiftMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
__ jmp(&done, Assembler::kNearJump);
__ Bind(&large_shift);
__ subl(ECX, Immediate(32));
// No need to subtract 32 from CL, only 5 bits used by sarl.
__ movl(left_lo, left_hi); // Shift by 32.
__ sarl(left_hi, Immediate(31)); // Sign extend left hi.
__ sarl(left_lo, ECX); // Shift count - 32 in CL.
__ sarl(left_lo, ECX); // Shift count: CL % 32.
break;
}
case Token::kSHL: {
@ -6086,10 +6085,10 @@ void ShiftMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
__ jmp(&done, Assembler::kNearJump);
__ Bind(&large_shift);
__ subl(ECX, Immediate(32));
// No need to subtract 32 from CL, only 5 bits used by shll.
__ movl(left_hi, left_lo); // Shift by 32.
__ xorl(left_lo, left_lo); // Zero left_lo.
__ shll(left_hi, ECX); // Shift count in CL.
__ shll(left_hi, ECX); // Shift count: CL % 32.
// Check for overflow by sign extending the high 32 bits
// and comparing with the input.
__ movl(temp2, left_hi);
@ -6105,10 +6104,10 @@ void ShiftMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
__ jmp(&done, Assembler::kNearJump);
__ Bind(&large_shift);
__ subl(ECX, Immediate(32));
// No need to subtract 32 from CL, only 5 bits used by shll.
__ movl(left_hi, left_lo); // Shift by 32.
__ xorl(left_lo, left_lo); // Zero left_lo.
__ shll(left_hi, ECX); // Shift count in CL.
__ shll(left_hi, ECX); // Shift count: CL % 32.
}
break;
}

8
runtime/vm/locations.cc
View file

@ -84,6 +84,14 @@ Location Location::RegisterOrSmiConstant(Value* value) {
}
Location Location::WritableRegisterOrSmiConstant(Value* value) {
ConstantInstr* constant = value->definition()->AsConstant();
return ((constant != NULL) && Assembler::IsSafeSmi(constant->value()))
? Location::Constant(constant->value())
: Location::WritableRegister();
}
Location Location::FixedRegisterOrConstant(Value* value, Register reg) {
ConstantInstr* constant = value->definition()->AsConstant();
return ((constant != NULL) && Assembler::IsSafe(constant->value()))

1
runtime/vm/locations.h
View file

@ -334,6 +334,7 @@ class Location : public ValueObject {
// Constants.
static Location RegisterOrConstant(Value* value);
static Location RegisterOrSmiConstant(Value* value);
static Location WritableRegisterOrSmiConstant(Value* value);
static Location FixedRegisterOrConstant(Value* value, Register reg);
static Location FixedRegisterOrSmiConstant(Value* value, Register reg);
static Location AnyOrConstant(Value* value);