[InstructionCombining] prepareICWorklistFromFunction halts in infinite loop with instructions of token type

Summary: This patch fixes a bug in prepareICWorklistFromFunction, where the loop becomes infinite with instructions of token type. The patch checks if the instruction is token type, and if so it updates EndInst with the current instruction.

Reviewers: reames, majnemer

Subscribers: llvm-commits, sanjoy

Differential Revision: http://reviews.llvm.org/D15859

llvm-svn: 256792

1 files changed, 2 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 7c46cfd..903a0b5 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3021,7 +3021,7 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
       Instruction *Inst = &*--EndInst->getIterator();
       if (!Inst->use_empty() && !Inst->getType()->isTokenTy())
         Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
-      if (Inst->isEHPad()) {
+      if (Inst->isEHPad() || Inst->getType()->isTokenTy()) {
         EndInst = Inst;
         continue;
       }
@@ -3029,8 +3029,7 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
         ++NumDeadInst;
         MadeIRChange = true;
       }
-      if (!Inst->getType()->isTokenTy())
-        Inst->eraseFromParent();
+      Inst->eraseFromParent();
     }
   }