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[CaptureTracker] Provide an ordered basic block to PointerMayBeCapturedBefore

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This patch is a follow up from r240560 and is a step further into
mitigating the compile time performance issues in CaptureTracker.

By providing the CaptureTracker with a "cached ordered basic block"
instead of computing it every time, MemDepAnalysis can use this cache
throughout its calls to AA->callCapturesBefore, avoiding to recompute it
for every scanned instruction. In the same testcase used in r240560,
compile time is reduced from 2min to 30s.

This also fixes PR22348.

rdar://problem/19230319
Differential Revision: http://reviews.llvm.org/D11364

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243750 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bruno Cardoso Lopes
2015-07-31 14:31:35 +00:00
parent 289b5e7f39
commit 8fea35acad
8 changed files with 205 additions and 81 deletions
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18
lib/Analysis/AliasAnalysis.cpp
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@ -335,13 +335,18 @@ ModRefInfo AliasAnalysis::getModRefInfo(const AtomicRMWInst *RMW,
return MRI_ModRef;
}
// FIXME: this is really just shoring-up a deficiency in alias analysis.
// BasicAA isn't willing to spend linear time determining whether an alloca
// was captured before or after this particular call, while we are. However,
// with a smarter AA in place, this test is just wasting compile time.
/// \brief Return information about whether a particular call site modifies
/// or reads the specified memory location \p MemLoc before instruction \p I
/// in a BasicBlock. A ordered basic block \p OBB can be used to speed up
/// instruction-ordering queries inside the BasicBlock containing \p I.
/// FIXME: this is really just shoring-up a deficiency in alias analysis.
/// BasicAA isn't willing to spend linear time determining whether an alloca
/// was captured before or after this particular call, while we are. However,
/// with a smarter AA in place, this test is just wasting compile time.
ModRefInfo AliasAnalysis::callCapturesBefore(const Instruction *I,
const MemoryLocation &MemLoc,
DominatorTree *DT) {
DominatorTree *DT,
OrderedBasicBlock *OBB) {
if (!DT)
return MRI_ModRef;
@ -356,7 +361,8 @@ ModRefInfo AliasAnalysis::callCapturesBefore(const Instruction *I,
if (llvm::PointerMayBeCapturedBefore(Object, /* ReturnCaptures */ true,
/* StoreCaptures */ true, I, DT,
/* include Object */ true))
/* include Object */ true,
/* OrderedBasicBlock */ OBB))
return MRI_ModRef;
unsigned ArgNo = 0;