Reviewers: ulan, jochen (OOO until March 10),
Description:
A64: Improve constraints on StoreKeyed instructions
BUG=
Please review this at https://codereview.chromium.org/190783002/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+19, -16 lines):
M src/a64/lithium-a64.cc
M src/a64/lithium-codegen-a64.cc
Index: src/a64/lithium-a64.cc
diff --git a/src/a64/lithium-a64.cc b/src/a64/lithium-a64.cc
index
cf89c09f5b2515d2dbc0b6cabe667b10245eb9ea..38f9c731041430afd0955a52e42194d4e695fb5b
100644
--- a/src/a64/lithium-a64.cc
+++ b/src/a64/lithium-a64.cc
@@ -2169,7 +2169,7 @@ LInstruction*
LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
LOperand* temp = NULL;
LOperand* elements = NULL;
LOperand* val = NULL;
- LOperand* key = NULL;
+ LOperand* key = UseRegisterOrConstantAtStart(instr->key());
if (!instr->is_typed_elements() &&
instr->value()->representation().IsTagged() &&
@@ -2177,11 +2177,11 @@ LInstruction*
LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
// RecordWrite() will clobber all registers.
elements = UseRegisterAndClobber(instr->elements());
val = UseRegisterAndClobber(instr->value());
- key = UseRegisterAndClobber(instr->key());
+ temp = TempRegister();
} else {
elements = UseRegister(instr->elements());
val = UseRegister(instr->value());
- key = UseRegisterOrConstantAtStart(instr->key());
+ temp = instr->key()->IsConstant() ? NULL : TempRegister();
}
if (instr->is_typed_elements()) {
@@ -2193,23 +2193,16 @@ LInstruction*
LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
instr->elements()->representation().IsTagged()) ||
(instr->is_external() &&
instr->elements()->representation().IsExternal()));
- temp = instr->key()->IsConstant() ? NULL : TempRegister();
return new(zone()) LStoreKeyedExternal(elements, key, val, temp);
} else if (instr->value()->representation().IsDouble()) {
ASSERT(instr->elements()->representation().IsTagged());
-
- // The constraint used here is UseRegister, even though the StoreKeyed
- // instruction may canonicalize the value in the register if it is a
NaN.
- temp = TempRegister();
return new(zone()) LStoreKeyedFixedDouble(elements, key, val, temp);
} else {
ASSERT(instr->elements()->representation().IsTagged());
ASSERT(instr->value()->representation().IsSmiOrTagged() ||
instr->value()->representation().IsInteger32());
-
- temp = TempRegister();
return new(zone()) LStoreKeyedFixed(elements, key, val, temp);
}
}
Index: src/a64/lithium-codegen-a64.cc
diff --git a/src/a64/lithium-codegen-a64.cc b/src/a64/lithium-codegen-a64.cc
index
ad8d742abac2cc894d292e026d7005b67933e834..d7dd832a8593385765f39f2107deb17f77b3e94a
100644
--- a/src/a64/lithium-codegen-a64.cc
+++ b/src/a64/lithium-codegen-a64.cc
@@ -5059,7 +5059,7 @@ void
LCodeGen::DoStoreKeyedExternal(LStoreKeyedExternal* instr) {
void LCodeGen::DoStoreKeyedFixedDouble(LStoreKeyedFixedDouble* instr) {
Register elements = ToRegister(instr->elements());
DoubleRegister value = ToDoubleRegister(instr->value());
- Register store_base = ToRegister(instr->temp());
+ Register store_base = no_reg;
int offset = 0;
if (instr->key()->IsConstantOperand()) {
@@ -5071,6 +5071,7 @@ void
LCodeGen::DoStoreKeyedFixedDouble(LStoreKeyedFixedDouble* instr) {
instr->additional_index());
store_base = elements;
} else {
+ store_base = ToRegister(instr->temp());
Register key = ToRegister(instr->key());
bool key_is_tagged =
instr->hydrogen()->key()->representation().IsSmi();
CalcKeyedArrayBaseRegister(store_base, elements, key, key_is_tagged,
@@ -5093,17 +5094,23 @@ void
LCodeGen::DoStoreKeyedFixedDouble(LStoreKeyedFixedDouble* instr) {
void LCodeGen::DoStoreKeyedFixed(LStoreKeyedFixed* instr) {
Register value = ToRegister(instr->value());
Register elements = ToRegister(instr->elements());
- Register store_base = ToRegister(instr->temp());
+ Register scratch = no_reg;
+ Register store_base = no_reg;
Register key = no_reg;
int offset = 0;
+ if (!instr->key()->IsConstantOperand() ||
+ instr->hydrogen()->NeedsWriteBarrier()) {
+ scratch = ToRegister(instr->temp());
+ }
+
if (instr->key()->IsConstantOperand()) {
- ASSERT(!instr->hydrogen()->NeedsWriteBarrier());
LConstantOperand* const_operand = LConstantOperand::cast(instr->key());
offset = FixedArray::OffsetOfElementAt(ToInteger32(const_operand) +
instr->additional_index());
store_base = elements;
} else {
+ store_base = scratch;
key = ToRegister(instr->key());
bool key_is_tagged =
instr->hydrogen()->key()->representation().IsSmi();
CalcKeyedArrayBaseRegister(store_base, elements, key, key_is_tagged,
@@ -5122,13 +5129,16 @@ void LCodeGen::DoStoreKeyedFixed(LStoreKeyedFixed*
instr) {
}
if (instr->hydrogen()->NeedsWriteBarrier()) {
+ ASSERT(representation.IsTagged());
+ // This assignment may cause element_addr to alias store_base.
+ Register element_addr = scratch;
SmiCheck check_needed =
instr->hydrogen()->value()->IsHeapObject()
? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
// Compute address of modified element and store it into key register.
- __ Add(key, store_base, offset - kHeapObjectTag);
- __ RecordWrite(elements, key, value, GetLinkRegisterState(),
kSaveFPRegs,
- EMIT_REMEMBERED_SET, check_needed);
+ __ Add(element_addr, store_base, offset - kHeapObjectTag);
+ __ RecordWrite(elements, element_addr, value, GetLinkRegisterState(),
+ kSaveFPRegs, EMIT_REMEMBERED_SET, check_needed);
}
}
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