ValueTracking: introduce llvm::isNotCrossLaneOperation (#112011)

Factor out and unify common code from InstSimplify and InstCombine that
partially guard against cross-lane vector operations into
llvm::isNotCrossLaneOperation in ValueTracking.

Alive2 proofs for changed tests: https://alive2.llvm.org/ce/z/68H4ka

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 446ff42..4e76f35 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -6947,6 +6947,29 @@ bool llvm::onlyUsedByLifetimeMarkersOrDroppableInsts(const Value *V) {
       V, /* AllowLifetime */ true, /* AllowDroppable */ true);
 }
 
+bool llvm::isNotCrossLaneOperation(const Instruction *I) {
+  if (auto *II = dyn_cast<IntrinsicInst>(I)) {
+    switch (II->getIntrinsicID()) {
+    // TODO: expand this list.
+    case Intrinsic::ctlz:
+    case Intrinsic::cttz:
+    case Intrinsic::ctpop:
+    case Intrinsic::umin:
+    case Intrinsic::umax:
+    case Intrinsic::smin:
+    case Intrinsic::smax:
+    case Intrinsic::usub_sat:
+    case Intrinsic::uadd_sat:
+    case Intrinsic::ssub_sat:
+    case Intrinsic::sadd_sat:
+      return true;
+    default:
+      return false;
+    }
+  }
+  return !isa<CallBase, BitCastInst, ShuffleVectorInst, ExtractElementInst>(I);
+}
+
 bool llvm::isSafeToSpeculativelyExecute(const Instruction *Inst,
                                         const Instruction *CtxI,
                                         AssumptionCache *AC,