Revision: 21899
Author: [email protected]
Date: Fri Jun 20 11:26:17 2014 UTC
Log: ARM: Avoid duplicate vmla when merging vmul and vadd
Avoid generating duplicate vmla instructions for vmul/vadd sequences where
the
vmul has more than one use.
For example: function f(a, b, c) { return (a * b) + c + (a * b); }
Previously, this would produce a vmul for the subexpression (a * b), then
vmla
for (a * b) + c, then vmla for (a * b) + [(a * b) + c].
Now it produces vmul, vadd, vadd, as expected.
BUG=
[email protected]
Review URL: https://codereview.chromium.org/323423003
http://code.google.com/p/v8/source/detail?r=21899
Modified:
/branches/bleeding_edge/src/arm/lithium-arm.cc
/branches/bleeding_edge/src/hydrogen-instructions.cc
/branches/bleeding_edge/src/hydrogen-instructions.h
/branches/bleeding_edge/src/mips/lithium-mips.cc
=======================================
--- /branches/bleeding_edge/src/arm/lithium-arm.cc Fri Jun 20 08:40:11 2014
UTC
+++ /branches/bleeding_edge/src/arm/lithium-arm.cc Fri Jun 20 11:26:17 2014
UTC
@@ -1500,8 +1500,8 @@
return DefineAsRegister(mul);
} else if (instr->representation().IsDouble()) {
- if (instr->UseCount() == 1 && (instr->uses().value()->IsAdd() ||
- instr->uses().value()->IsSub())) {
+ if (instr->HasOneUse() && (instr->uses().value()->IsAdd() ||
+ instr->uses().value()->IsSub())) {
HBinaryOperation* use =
HBinaryOperation::cast(instr->uses().value());
if (use->IsAdd() && instr == use->left()) {
@@ -1547,7 +1547,7 @@
}
return result;
} else if (instr->representation().IsDouble()) {
- if (instr->right()->IsMul()) {
+ if (instr->right()->IsMul() && instr->right()->HasOneUse()) {
return DoMultiplySub(instr->left(), HMul::cast(instr->right()));
}
@@ -1618,12 +1618,12 @@
LInstruction* result = DefineAsRegister(add);
return result;
} else if (instr->representation().IsDouble()) {
- if (instr->left()->IsMul()) {
+ if (instr->left()->IsMul() && instr->left()->HasOneUse()) {
return DoMultiplyAdd(HMul::cast(instr->left()), instr->right());
}
- if (instr->right()->IsMul()) {
- ASSERT(!instr->left()->IsMul());
+ if (instr->right()->IsMul() && instr->right()->HasOneUse()) {
+ ASSERT(!instr->left()->IsMul() || !instr->left()->HasOneUse());
return DoMultiplyAdd(HMul::cast(instr->right()), instr->left());
}
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.cc Fri Jun 20
08:40:11 2014 UTC
+++ /branches/bleeding_edge/src/hydrogen-instructions.cc Fri Jun 20
11:26:17 2014 UTC
@@ -1581,7 +1581,7 @@
val, representation(), false, false));
}
}
- if (op() == kMathFloor && value()->IsDiv() && value()->UseCount() == 1) {
+ if (op() == kMathFloor && value()->IsDiv() && value()->HasOneUse()) {
HDiv* hdiv = HDiv::cast(value());
HValue* left = hdiv->left();
@@ -2149,7 +2149,7 @@
added_index()->SetOperandAt(1, index_base);
added_index()->SetOperandAt(2, added_constant());
first_check_in_block()->SetOperandAt(0, added_index());
- if (previous_index->UseCount() == 0) {
+ if (previous_index->HasNoUses()) {
previous_index->DeleteAndReplaceWith(NULL);
}
}
@@ -2893,7 +2893,7 @@
// TODO(titzer): this seems like a hack that should be fixed by custom
OSR.
return true;
}
- if (UseCount() == 0) return true;
+ if (HasNoUses()) return true;
if (IsCell()) return false;
if (representation().IsDouble()) return false;
if (representation().IsExternal()) return false;
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.h Mon Jun 16 13:03:59
2014 UTC
+++ /branches/bleeding_edge/src/hydrogen-instructions.h Fri Jun 20 11:26:17
2014 UTC
@@ -663,6 +663,9 @@
void DeleteAndReplaceWith(HValue* other);
void ReplaceAllUsesWith(HValue* other);
bool HasNoUses() const { return use_list_ == NULL; }
+ bool HasOneUse() const {
+ return use_list_ != NULL && use_list_->tail() == NULL;
+ }
bool HasMultipleUses() const {
return use_list_ != NULL && use_list_->tail() != NULL;
}
@@ -3760,7 +3763,7 @@
// Otherwise, if there is only one use of the right operand, it would
be
// better off on the left for platforms that only have 2-arg arithmetic
// ops (e.g ia32, x64) that clobber the left operand.
- return right()->UseCount() == 1;
+ return right()->HasOneUse();
}
HValue* BetterLeftOperand() {
=======================================
--- /branches/bleeding_edge/src/mips/lithium-mips.cc Fri Jun 20 08:40:11
2014 UTC
+++ /branches/bleeding_edge/src/mips/lithium-mips.cc Fri Jun 20 11:26:17
2014 UTC
@@ -1492,7 +1492,7 @@
} else if (instr->representation().IsDouble()) {
if (kArchVariant == kMips32r2) {
- if (instr->UseCount() == 1 && instr->uses().value()->IsAdd()) {
+ if (instr->HasOneUse() && instr->uses().value()->IsAdd()) {
HAdd* add = HAdd::cast(instr->uses().value());
if (instr == add->left()) {
// This mul is the lhs of an add. The add and mul will be folded
--
--
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