[MergeICmp] Simplify how BCECmpBlock instructions are blacklisted

llvm-svn: 326761

1 files changed, 4 insertions, 10 deletions

diff --git a/llvm/lib/Transforms/Scalar/MergeICmps.cpp b/llvm/lib/Transforms/Scalar/MergeICmps.cpp
index 3a5431b5171..4e54f1e47e7 100644
--- a/llvm/lib/Transforms/Scalar/MergeICmps.cpp
+++ b/llvm/lib/Transforms/Scalar/MergeICmps.cpp
@@ -159,22 +159,16 @@ class BCECmpBlock {
 
 bool BCECmpBlock::doesOtherWork() const {
   AssertConsistent();
+  // All the instructions we care about in the BCE cmp block.
+  DenseSet<Instruction *> BlockInsts(
+      {Lhs_.GEP, Rhs_.GEP, Lhs_.LoadI, Rhs_.LoadI, CmpI, BranchI});
   // TODO(courbet): Can we allow some other things ? This is very conservative.
   // We might be able to get away with anything does does not have any side
   // effects outside of the basic block.
   // Note: The GEPs and/or loads are not necessarily in the same block.
   for (const Instruction &Inst : *BB) {
-    if (const auto *const GEP = dyn_cast<GetElementPtrInst>(&Inst)) {
-      if (!(Lhs_.GEP == GEP || Rhs_.GEP == GEP)) return true;
-    } else if (const auto *const L = dyn_cast<LoadInst>(&Inst)) {
-      if (!(Lhs_.LoadI == L || Rhs_.LoadI == L)) return true;
-    } else if (const auto *const C = dyn_cast<ICmpInst>(&Inst)) {
-      if (C != CmpI) return true;
-    } else if (const auto *const Br = dyn_cast<BranchInst>(&Inst)) {
-      if (Br != BranchI) return true;
-    } else {
+    if (!BlockInsts.count(&Inst))
       return true;
-    }
   }
   return false;
 }