[llvm-commits] [llvm] r160546 - in /llvm/trunk: lib/Transforms/Scalar/JumpThreading.cpp test/Transforms/JumpThreading/2012-07-19-NoSuccessorIndirectBr.ll

[Richard Osborne]

Author: friedgold
Date: Fri Jul 20 05:36:17 2012
New Revision: 160546

URL: http://llvm.org/viewvc/llvm-project?rev=160546&view=rev
Log:
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.


Added:
    llvm/trunk/test/Transforms/JumpThreading/2012-07-19-NoSuccessorIndirectBr.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp?rev=160546&r1=160545&r2=160546&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp Fri Jul 20 05:36:17 2012
@@ -670,6 +670,8 @@
   } 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 {

Added: llvm/trunk/test/Transforms/JumpThreading/2012-07-19-NoSuccessorIndirectBr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/JumpThreading/2012-07-19-NoSuccessorIndirectBr.ll?rev=160546&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/JumpThreading/2012-07-19-NoSuccessorIndirectBr.ll (added)
+++ llvm/trunk/test/Transforms/JumpThreading/2012-07-19-NoSuccessorIndirectBr.ll Fri Jul 20 05:36:17 2012
@@ -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, []
+}