Title: [96482] trunk/Source/_javascript_Core
- Revision
- 96482
- Author
- [email protected]
- Date
- 2011-10-02 19:13:11 -0700 (Sun, 02 Oct 2011)
Log Message
DFG misses some obvious opportunities for common subexpression elimination
https://bugs.webkit.org/show_bug.cgi?id=69233
Reviewed by Oliver Hunt.
0.7% speed-up on SunSpider.
* dfg/DFGPropagator.cpp:
(JSC::DFG::Propagator::getByValLoadElimination):
(JSC::DFG::Propagator::getMethodLoadElimination):
(JSC::DFG::Propagator::checkStructureLoadElimination):
(JSC::DFG::Propagator::getByOffsetLoadElimination):
(JSC::DFG::Propagator::getPropertyStorageLoadElimination):
(JSC::DFG::Propagator::performNodeCSE):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (96481 => 96482)
--- trunk/Source/_javascript_Core/ChangeLog 2011-10-03 01:11:45 UTC (rev 96481)
+++ trunk/Source/_javascript_Core/ChangeLog 2011-10-03 02:13:11 UTC (rev 96482)
@@ -1,3 +1,20 @@
+2011-10-02 Filip Pizlo <[email protected]>
+
+ DFG misses some obvious opportunities for common subexpression elimination
+ https://bugs.webkit.org/show_bug.cgi?id=69233
+
+ Reviewed by Oliver Hunt.
+
+ 0.7% speed-up on SunSpider.
+
+ * dfg/DFGPropagator.cpp:
+ (JSC::DFG::Propagator::getByValLoadElimination):
+ (JSC::DFG::Propagator::getMethodLoadElimination):
+ (JSC::DFG::Propagator::checkStructureLoadElimination):
+ (JSC::DFG::Propagator::getByOffsetLoadElimination):
+ (JSC::DFG::Propagator::getPropertyStorageLoadElimination):
+ (JSC::DFG::Propagator::performNodeCSE):
+
2011-10-02 Gavin Barraclough <[email protected]>
Bug 67455 - Different regular _expression_ result
Modified: trunk/Source/_javascript_Core/dfg/DFGPropagator.cpp (96481 => 96482)
--- trunk/Source/_javascript_Core/dfg/DFGPropagator.cpp 2011-10-03 01:11:45 UTC (rev 96481)
+++ trunk/Source/_javascript_Core/dfg/DFGPropagator.cpp 2011-10-03 02:13:11 UTC (rev 96482)
@@ -964,11 +964,18 @@
if (node.child1() == child1 && canonicalize(node.child2()) == canonicalize(child2))
return node.child3();
break;
+ case PutStructure:
+ case PutByOffset:
+ // GetByVal currently always speculates that it's accessing an
+ // array with an integer index, which means that it's impossible
+ // for a structure change or a put to property storage to affect
+ // the GetByVal.
+ break;
default:
+ if (clobbersWorld(index))
+ return NoNode;
break;
}
- if (clobbersWorld(index))
- break;
}
return NoNode;
}
@@ -978,13 +985,30 @@
NodeIndex start = startIndexForChildren(child1);
for (NodeIndex index = m_compileIndex; index-- > start;) {
Node& node = m_graph[index];
- if (node.op == CheckMethod
- && node.child1() == child1
- && node.identifierNumber() == identifierNumber
- && m_graph.m_methodCheckData[node.methodCheckDataIndex()] == methodCheckData)
- return index;
- if (clobbersWorld(index))
+ switch (node.op) {
+ case CheckMethod:
+ if (node.child1() == child1
+ && node.identifierNumber() == identifierNumber
+ && m_graph.m_methodCheckData[node.methodCheckDataIndex()] == methodCheckData)
+ return index;
break;
+
+ case PutByOffset:
+ // If a put was optimized to by-offset then it's not changing the structure
+ break;
+
+ case PutByVal:
+ case PutByValAlias:
+ // PutByVal currently always speculates that it's accessing an array with an
+ // integer index, which means that it's impossible for it to cause a structure
+ // change.
+ break;
+
+ default:
+ if (clobbersWorld(index))
+ return NoNode;
+ break;
+ }
}
return NoNode;
}
@@ -1011,6 +1035,13 @@
// Setting a property cannot change the structure.
break;
+ case PutByVal:
+ case PutByValAlias:
+ // PutByVal currently always speculates that it's accessing an array with an
+ // integer index, which means that it's impossible for it to cause a structure
+ // change.
+ break;
+
default:
if (clobbersWorld(index))
return false;
@@ -1044,6 +1075,13 @@
// Changing the structure cannot change the outcome of a property get.
break;
+ case PutByVal:
+ case PutByValAlias:
+ // PutByVal currently always speculates that it's accessing an array with an
+ // integer index, which means that it's impossible for it to cause a structure
+ // change.
+ break;
+
default:
if (clobbersWorld(index))
return NoNode;
@@ -1070,6 +1108,13 @@
// change the property storage pointer.
break;
+ case PutByVal:
+ case PutByValAlias:
+ // PutByVal currently always speculates that it's accessing an array with an
+ // integer index, which means that it's impossible for it to cause a structure
+ // change.
+ break;
+
default:
if (clobbersWorld(index))
return NoNode;
@@ -1191,11 +1236,14 @@
case ArithMax:
case ArithSqrt:
case GetCallee:
- case GetArrayLength:
case GetStringLength:
setReplacement(pureCSE(node));
break;
+ case GetArrayLength:
+ setReplacement(impureCSE(node));
+ break;
+
case GetScopeChain:
setReplacement(getScopeChainLoadElimination(node.scopeChainDepth()));
break;
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