Changes in directory llvm/lib/Transforms/Scalar:
SCCP.cpp updated: 1.134 -> 1.135
---
Log message:
Handle fallout from the recent branch-on-undef changes. This fixes
Prolangs-C/agrep and SCCP/2006-10-23-IPSCCP-Crash.ll
---
Diffs of the changes: (+24 -1)
SCCP.cpp | 25 ++++++++++++++++++++++++-
1 files changed, 24 insertions(+), 1 deletion(-)
Index: llvm/lib/Transforms/Scalar/SCCP.cpp
diff -u llvm/lib/Transforms/Scalar/SCCP.cpp:1.134
llvm/lib/Transforms/Scalar/SCCP.cpp:1.135
--- llvm/lib/Transforms/Scalar/SCCP.cpp:1.134 Sun Oct 22 00:59:17 2006
+++ llvm/lib/Transforms/Scalar/SCCP.cpp Mon Oct 23 13:57:02 2006
@@ -1360,7 +1360,30 @@
while (!DeadBB->use_empty()) {
Instruction *I = cast<Instruction>(DeadBB->use_back());
bool Folded = ConstantFoldTerminator(I->getParent());
- assert(Folded && "Didn't fold away reference to block!");
+ if (!Folded) {
+ // The constant folder may not have been able to fold the termiantor
+ // if this is a branch or switch on undef. Fold it manually as a
+ // branch to the first successor.
+ if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
+ assert(BI->isConditional() && isa<UndefValue>(BI->getCondition())
&&
+ "Branch should be foldable!");
+ } else if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
+ assert(isa<UndefValue>(SI->getCondition()) && "Switch should
fold");
+ } else {
+ assert(0 && "Didn't fold away reference to block!");
+ }
+
+ // Make this an uncond branch to the first successor.
+ TerminatorInst *TI = I->getParent()->getTerminator();
+ new BranchInst(TI->getSuccessor(0), TI);
+
+ // Remove entries in successor phi nodes to remove edges.
+ for (unsigned i = 1, e = TI->getNumSuccessors(); i != e; ++i)
+ TI->getSuccessor(i)->removePredecessor(TI->getParent());
+
+ // Remove the old terminator.
+ TI->eraseFromParent();
+ }
}
// Finally, delete the basic block.
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