Reviewers: danno,
Description:
Cleaned up nil comparisons in Hydrogen.
This consists basically of 2 parts:
* Restructured BuildCompareNil to make the logic behind it clearer.
Note that it is intentionally written in a quite stylized way.
* Replaced a usesless IfBuilder by a plain HInstruction, removing
some empty blocks.
Please review this at https://codereview.chromium.org/22305004/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/hydrogen.cc
Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index
f7ef91a088d9ea639a80089fc62ef85d39ed79be..6ac8a1db899a142abe97b0926288256fb8f75dc1
100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -1725,22 +1725,35 @@ void HGraphBuilder::BuildCompareNil(
int position,
HIfContinuation* continuation) {
IfBuilder if_nil(this, position);
- bool needs_or = false;
+ bool some_case_handled = false;
+ bool some_case_missing = false;
+
if (type->Maybe(Type::Null())) {
- if (needs_or) if_nil.Or();
+ if (some_case_handled) if_nil.Or();
if_nil.If<HCompareObjectEqAndBranch>(value,
graph()->GetConstantNull());
- needs_or = true;
+ some_case_handled = true;
+ } else {
+ some_case_missing = true;
}
+
if (type->Maybe(Type::Undefined())) {
- if (needs_or) if_nil.Or();
+ if (some_case_handled) if_nil.Or();
if_nil.If<HCompareObjectEqAndBranch>(value,
graph()->GetConstantUndefined());
- needs_or = true;
+ some_case_handled = true;
+ } else {
+ some_case_missing = true;
}
+
if (type->Maybe(Type::Undetectable())) {
- if (needs_or) if_nil.Or();
+ if (some_case_handled) if_nil.Or();
if_nil.If<HIsUndetectableAndBranch>(value);
+ some_case_handled = true;
} else {
+ some_case_missing = true;
+ }
+
+ if (some_case_missing) {
if_nil.Then();
if_nil.Else();
if (type->NumClasses() == 1) {
@@ -8064,21 +8077,23 @@ void
HOptimizedGraphBuilder::HandleLiteralCompareNil(CompareOperation* expr,
ASSERT(expr->op() == Token::EQ || expr->op() == Token::EQ_STRICT);
CHECK_ALIVE(VisitForValue(sub_expr));
HValue* value = Pop();
- HIfContinuation continuation;
if (expr->op() == Token::EQ_STRICT) {
- IfBuilder if_nil(this);
- if_nil.If<HCompareObjectEqAndBranch>(
- value, (nil == kNullValue) ? graph()->GetConstantNull()
- : graph()->GetConstantUndefined());
- if_nil.Then();
- if_nil.Else();
- if_nil.CaptureContinuation(&continuation);
+ HConstant* nil_constant = nil == kNullValue
+ ? graph()->GetConstantNull()
+ : graph()->GetConstantUndefined();
+ HCompareObjectEqAndBranch* instr =
+ New<HCompareObjectEqAndBranch>(value, nil_constant);
+ instr->set_position(expr->position());
+ return ast_context()->ReturnControl(instr, expr->id());
+ } else {
+ ASSERT_EQ(Token::EQ, expr->op());
+ Handle<Type> type = expr->combined_type()->Is(Type::None())
+ ? handle(Type::Any(), isolate_)
+ : expr->combined_type();
+ HIfContinuation continuation;
+ BuildCompareNil(value, type, expr->position(), &continuation);
return ast_context()->ReturnContinuation(&continuation, expr->id());
}
- Handle<Type> type = expr->combined_type()->Is(Type::None())
- ? handle(Type::Any(), isolate_) : expr->combined_type();
- BuildCompareNil(value, type, expr->position(), &continuation);
- return ast_context()->ReturnContinuation(&continuation, expr->id());
}
--
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