Reviewers: Mads Ager,
Description:
Cut-and-paste port from ia32 to x64: Delay load of trivial left operand of
binary operation until after right operand loaded.
Please review this at http://codereview.chromium.org/1736023/show
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/x64/codegen-x64.cc
M src/x64/virtual-frame-x64.h
M src/x64/virtual-frame-x64.cc
Index: src/x64/virtual-frame-x64.cc
===================================================================
--- src/x64/virtual-frame-x64.cc (revision 4545)
+++ src/x64/virtual-frame-x64.cc (working copy)
@@ -226,6 +226,31 @@
}
+void VirtualFrame::Push(Expression* expr) {
+ ASSERT(expr->IsTrivial());
+
+ Literal* lit = expr->AsLiteral();
+ if (lit != NULL) {
+ Push(lit->handle());
+ return;
+ }
+
+ VariableProxy* proxy = expr->AsVariableProxy();
+ if (proxy != NULL) {
+ Slot* slot = proxy->var()->slot();
+ if (slot->type() == Slot::LOCAL) {
+ PushLocalAt(slot->index());
+ return;
+ }
+ if (slot->type() == Slot::PARAMETER) {
+ PushParameterAt(slot->index());
+ return;
+ }
+ }
+ UNREACHABLE();
+}
+
+
void VirtualFrame::Drop(int count) {
ASSERT(count >= 0);
ASSERT(height() >= count);
Index: src/x64/virtual-frame-x64.h
===================================================================
--- src/x64/virtual-frame-x64.h (revision 4545)
+++ src/x64/virtual-frame-x64.h (working copy)
@@ -415,6 +415,10 @@
result->Unuse();
}
+ // Pushing an expression expects that the expression is trivial
(according
+ // to Expression::IsTrivial).
+ void Push(Expression* expr);
+
// Nip removes zero or more elements from immediately below the top
// of the frame, leaving the previous top-of-frame value on top of
// the frame. Nip(k) is equivalent to x = Pop(), Drop(k), Push(x).
Index: src/x64/codegen-x64.cc
===================================================================
--- src/x64/codegen-x64.cc (revision 4545)
+++ src/x64/codegen-x64.cc (working copy)
@@ -3531,8 +3531,15 @@
overwrite_mode = OVERWRITE_RIGHT;
}
- Load(node->left());
- Load(node->right());
+ if (node->left()->IsTrivial()) {
+ Load(node->right());
+ Result right = frame_->Pop();
+ frame_->Push(node->left());
+ frame_->Push(&right);
+ } else {
+ Load(node->left());
+ Load(node->right());
+ }
GenericBinaryOperation(node->op(), node->type(), overwrite_mode);
}
}
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