An sinkable instruction may exist with uses, if those uses are in dead blocks.
Handle this. This fixes PR908 and Transforms/LICM/2006-09-12-DeadUserOfSunkInstr.ll
llvm-svn: 30275
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index a24b366..7ca9be0 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -447,6 +447,8 @@
if (!isExitBlockDominatedByBlockInLoop(ExitBlocks[0], I.getParent())) {
// Instruction is not used, just delete it.
CurAST->deleteValue(&I);
+ if (!I.use_empty()) // If I has users in unreachable blocks, eliminate.
+ I.replaceAllUsesWith(UndefValue::get(I.getType()));
I.eraseFromParent();
} else {
// Move the instruction to the start of the exit block, after any PHI
@@ -460,6 +462,8 @@
} else if (ExitBlocks.size() == 0) {
// The instruction is actually dead if there ARE NO exit blocks.
CurAST->deleteValue(&I);
+ if (!I.use_empty()) // If I has users in unreachable blocks, eliminate.
+ I.replaceAllUsesWith(UndefValue::get(I.getType()));
I.eraseFromParent();
} else {
// Otherwise, if we have multiple exits, use the PromoteMem2Reg function to