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fix PR6743, a case where we'd delete an instruction before using it 

in some cases.

llvm-svn: 100937
This commit is contained in:
Chris Lattner 2010-04-10 18:26:57 +00:00
parent b9801ffcb5
commit 9ae28b141f
2 changed files with 20 additions and 1 deletions
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4
llvm/lib/Transforms/Scalar/JumpThreading.cpp
View File

@ -670,8 +670,10 @@ bool JumpThreading::ProcessBranchOnDuplicateCond(BasicBlock *PredBB,
Value *OldCond = DestBI->getCondition();
DestBI->setCondition(ConstantInt::get(Type::getInt1Ty(BB->getContext()),
BranchDir));
ConstantFoldTerminator(BB);
// Delete dead instructions before we fold the branch. Folding the branch
// can eliminate edges from the CFG which can end up deleting OldCond.
RecursivelyDeleteTriviallyDeadInstructions(OldCond);
ConstantFoldTerminator(BB);
return true;
}

17
llvm/test/Transforms/JumpThreading/crash.ll
View File

@ -324,3 +324,20 @@ A: ; preds = %entry
call void undef(i64 ptrtoint (i8* blockaddress(@test11, %A) to i64)) nounwind
unreachable
}
; PR6743
define void @test12() nounwind ssp {
entry:
br label %lbl_51
lbl_51: ; preds = %if.then, %entry
%tmp3 = phi i1 [ false, %if.then ], [ undef, %entry ] ; <i1> [#uses=2]
br i1 %tmp3, label %if.end12, label %if.then
if.then: ; preds = %lbl_51
br i1 %tmp3, label %lbl_51, label %if.end12
if.end12: ; preds = %if.then, %lbl_51
ret void
}