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Oops, FunctionContainsEscapingAllocas is really used to mean two different

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things. Back out part of r86349 for a moment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86353 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2009-11-07 07:42:38 +00:00
parent 0cade26132
commit cb19438f63
2 changed files with 11 additions and 2 deletions
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12
lib/Transforms/Scalar/TailRecursionElimination.cpp
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@ -91,6 +91,15 @@ FunctionPass *llvm::createTailCallEliminationPass() {
return new TailCallElim();
}
/// AllocaMightEscapeToCalls - Return true if this alloca may be accessed by
/// callees of this function. We only do very simple analysis right now, this
/// could be expanded in the future to use mod/ref information for particular
/// call sites if desired.
static bool AllocaMightEscapeToCalls(AllocaInst *AI) {
// FIXME: do simple 'address taken' analysis.
return true;
}
/// CheckForEscapingAllocas - Scan the specified basic block for alloca
/// instructions. If it contains any that might be accessed by calls, return
/// true.
@ -99,7 +108,7 @@ static bool CheckForEscapingAllocas(BasicBlock *BB,
bool RetVal = false;
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
RetVal |= PointerMayBeCaptured(AI, true);
RetVal |= AllocaMightEscapeToCalls(AI);
// If this alloca is in the body of the function, or if it is a variable
// sized allocation, we cannot tail call eliminate calls marked 'tail'
@ -146,7 +155,6 @@ bool TailCallElim::runOnFunction(Function &F) {
if (FunctionContainsEscapingAllocas)
return false;
// Second pass, change any tail calls to loops.
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (ReturnInst *Ret = dyn_cast<ReturnInst>(BB->getTerminator()))

1
test/Transforms/TailCallElim/nocapture.ll
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@ -1,4 +1,5 @@
; RUN: opt %s -tailcallelim -S | FileCheck %s
; XFAIL: *
declare void @use(i8* nocapture, i8* nocapture)