Author: dim
Date: Tue Nov 19 17:53:19 2013
New Revision: 258350
URL: http://svnweb.freebsd.org/changeset/base/258350
Log:
Pull in r191896 from upstream llvm trunk:
CaptureTracking: Plug a loophole in the "too many uses" heuristic.
The heuristic was added to avoid spending too much compile time in a
specially crafted test case (PR17461, PR16474) with many uses on a
select or bitcast instruction can still trigger the slow case. Add a
check for that case.
This only affects compile time, don't have a good way to test it.
This fixes the excessive compile time spent on a specific file of the
graphics/rawtherapee port.
Reported by: mandree
MFC after: 3 days
Modified:
head/contrib/llvm/lib/Analysis/CaptureTracking.cpp
Modified: head/contrib/llvm/lib/Analysis/CaptureTracking.cpp
==============================================================================
--- head/contrib/llvm/lib/Analysis/CaptureTracking.cpp Tue Nov 19 16:11:03
2013 (r258349)
+++ head/contrib/llvm/lib/Analysis/CaptureTracking.cpp Tue Nov 19 17:53:19
2013 (r258350)
@@ -146,8 +146,14 @@ void llvm::PointerMayBeCaptured(const Va
case Instruction::PHI:
case Instruction::Select:
// The original value is not captured via this if the new value isn't.
+ Count = 0;
for (Instruction::use_iterator UI = I->use_begin(), UE = I->use_end();
UI != UE; ++UI) {
+ // If there are lots of uses, conservatively say that the value
+ // is captured to avoid taking too much compile time.
+ if (Count++ >= Threshold)
+ return Tracker->tooManyUses();
+
Use *U = &UI.getUse();
if (Visited.insert(U))
if (Tracker->shouldExplore(U))
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