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author | Duncan Sands <baldrick@free.fr> | 2010-06-26 12:53:31 +0000 |
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committer | Duncan Sands <baldrick@free.fr> | 2010-06-26 12:53:31 +0000 |
commit | d50e9e2566479301e687fc81e16dab7e3c2b50ea (patch) | |
tree | a7591ad25c85aba30c85d2f235391595dc4e4b53 /lib/Transforms/Scalar/TailRecursionElimination.cpp | |
parent | 7a1d92a2cbc20888260efa7d5ad987dc39fcb134 (diff) | |
download | llvm-d50e9e2566479301e687fc81e16dab7e3c2b50ea.tar.gz llvm-d50e9e2566479301e687fc81e16dab7e3c2b50ea.tar.bz2 llvm-d50e9e2566479301e687fc81e16dab7e3c2b50ea.tar.xz |
Fix PR7328: when turning a tail recursion into a loop, need to preserve
the returned value after the tail call if it differs from other return
values. The optimal thing to do would be to introduce a phi node for
the return value, but for the moment just fix the miscompile.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106947 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Scalar/TailRecursionElimination.cpp')
-rw-r--r-- | lib/Transforms/Scalar/TailRecursionElimination.cpp | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/lib/Transforms/Scalar/TailRecursionElimination.cpp b/lib/Transforms/Scalar/TailRecursionElimination.cpp index 42f4a5f71d..97e53e23d2 100644 --- a/lib/Transforms/Scalar/TailRecursionElimination.cpp +++ b/lib/Transforms/Scalar/TailRecursionElimination.cpp @@ -270,16 +270,16 @@ static bool isDynamicConstant(Value *V, CallInst *CI, ReturnInst *RI) { } // getCommonReturnValue - Check to see if the function containing the specified -// return instruction and tail call consistently returns the same -// runtime-constant value at all exit points. If so, return the returned value. +// tail call consistently returns the same runtime-constant value at all exit +// points except for IgnoreRI. If so, return the returned value. // -static Value *getCommonReturnValue(ReturnInst *TheRI, CallInst *CI) { - Function *F = TheRI->getParent()->getParent(); +static Value *getCommonReturnValue(ReturnInst *IgnoreRI, CallInst *CI) { + Function *F = CI->getParent()->getParent(); Value *ReturnedValue = 0; for (Function::iterator BBI = F->begin(), E = F->end(); BBI != E; ++BBI) if (ReturnInst *RI = dyn_cast<ReturnInst>(BBI->getTerminator())) - if (RI != TheRI) { + if (RI != IgnoreRI) { Value *RetOp = RI->getOperand(0); // We can only perform this transformation if the value returned is @@ -404,7 +404,7 @@ bool TailCallElim::ProcessReturningBlock(ReturnInst *Ret, BasicBlock *&OldEntry, if (Ret->getNumOperands() == 1 && Ret->getReturnValue() != CI && !isa<UndefValue>(Ret->getReturnValue()) && AccumulatorRecursionEliminationInitVal == 0 && - !getCommonReturnValue(Ret, CI)) + !getCommonReturnValue(0, CI)) return false; // OK! We can transform this tail call. If this is the first one found, |