Title: [194164] trunk/Source/_javascript_Core
- Revision
- 194164
- Author
- [email protected]
- Date
- 2015-12-16 11:10:55 -0800 (Wed, 16 Dec 2015)
Log Message
Work around a bug in LLVM by flipping the unification order
https://bugs.webkit.org/show_bug.cgi?id=152341
rdar://problem/23920749
Reviewed by Mark Lam.
* dfg/DFGUnificationPhase.cpp:
(JSC::DFG::UnificationPhase::run):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (194163 => 194164)
--- trunk/Source/_javascript_Core/ChangeLog 2015-12-16 19:02:42 UTC (rev 194163)
+++ trunk/Source/_javascript_Core/ChangeLog 2015-12-16 19:10:55 UTC (rev 194164)
@@ -1,3 +1,14 @@
+2015-12-16 Filip Pizlo <[email protected]>
+
+ Work around a bug in LLVM by flipping the unification order
+ https://bugs.webkit.org/show_bug.cgi?id=152341
+ rdar://problem/23920749
+
+ Reviewed by Mark Lam.
+
+ * dfg/DFGUnificationPhase.cpp:
+ (JSC::DFG::UnificationPhase::run):
+
2015-12-16 Saam barati <[email protected]>
Add "explicit operator bool" to ScratchRegisterAllocator::PreservedState
Modified: trunk/Source/_javascript_Core/dfg/DFGUnificationPhase.cpp (194163 => 194164)
--- trunk/Source/_javascript_Core/dfg/DFGUnificationPhase.cpp 2015-12-16 19:02:42 UTC (rev 194163)
+++ trunk/Source/_javascript_Core/dfg/DFGUnificationPhase.cpp 2015-12-16 19:10:55 UTC (rev 194164)
@@ -59,8 +59,12 @@
for (unsigned childIdx = 0; childIdx < AdjacencyList::Size; ++childIdx) {
if (!phi->children.child(childIdx))
break;
-
- phi->children.child(childIdx)->variableAccessData()->unify(phi->variableAccessData());
+
+ // We'd like to reverse the order of unification because it helps to reveal
+ // more bugs on our end, though it's otherwise not observable. But we do it
+ // this way because it works around a bug in open source LLVM's live-outs
+ // computation.
+ phi->variableAccessData()->unify(phi->children.child(childIdx)->variableAccessData());
}
}
}
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