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Fix assertion in jump threading (PR13405). 

GetBestDestForJumpOnUndef() assumes there is at least 1 successor, which isn't
true if the block ends in an indirect branch with no successors. Fix this by
bailing out earlier in this case.

llvm-svn: 160546
This commit is contained in:
Richard Osborne 2012-07-20 10:36:17 +00:00
parent f02c6069ac
commit 0ab2b0df82
2 changed files with 10 additions and 0 deletions
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2
llvm/lib/Transforms/Scalar/JumpThreading.cpp
View File

@ -670,6 +670,8 @@ bool JumpThreading::ProcessBlock(BasicBlock *BB) {
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(Terminator)) {
Condition = SI->getCondition();
} else if (IndirectBrInst *IB = dyn_cast<IndirectBrInst>(Terminator)) {
// Can't thread indirect branch with no successors.
if (IB->getNumSuccessors() == 0) return false;
Condition = IB->getAddress()->stripPointerCasts();
Preference = WantBlockAddress;
} else {

8
llvm/test/Transforms/JumpThreading/2012-07-19-NoSuccessorIndirectBr.ll Normal file
View File

@ -0,0 +1,8 @@
; RUN: opt < %s -jump-threading
; PR 13405
; Just check that it doesn't crash / assert
define i32 @f() nounwind {
entry:
indirectbr i8* undef, []
}