!fixup re-add unrelated code removed by accident

Author: fhahn

llvm/lib/Analysis/Loads.cpp

@@ -333,6 +333,14 @@ bool llvm::isDereferenceableAndAlignedInLoop(
   if (isa<SCEVCouldNotCompute>(MaxBECount))
     return false;
 
+  if (isa<SCEVCouldNotCompute>(BECount)) {
+    // TODO: Support symbolic max backedge taken counts for loops without
+    // computable backedge taken counts.
+    MaxBECount =
+        Predicates
+            ? SE.getPredicatedConstantMaxBackedgeTakenCount(L, *Predicates)
+            : SE.getConstantMaxBackedgeTakenCount(L);
+  }
   const auto &[AccessStart, AccessEnd] = getStartAndEndForAccess(
       L, PtrScev, LI->getType(), BECount, MaxBECount, &SE, nullptr, &DT, AC);
   if (isa<SCEVCouldNotCompute>(AccessStart) ||

llvm/test/Transforms/LoopVectorize/single-early-exit-deref-assumptions.ll

@@ -13,11 +13,9 @@ define i64 @early_exit_alignment_and_deref_known_via_assumption_with_constant_si
 ; CHECK:       vector.body:
 ; CHECK-NEXT:    [[INDEX1:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT3:%.*]], [[LOOP]] ]
 ; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[INDEX1]]
-; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
-; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP1]], align 1
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP0]], align 1
 ; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[INDEX1]]
-; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
-; CHECK-NEXT:    [[WIDE_LOAD2:%.*]] = load <4 x i8>, ptr [[TMP3]], align 1
+; CHECK-NEXT:    [[WIDE_LOAD2:%.*]] = load <4 x i8>, ptr [[TMP2]], align 1
 ; CHECK-NEXT:    [[TMP4:%.*]] = icmp ne <4 x i8> [[WIDE_LOAD]], [[WIDE_LOAD2]]
 ; CHECK-NEXT:    [[INDEX_NEXT3]] = add nuw i64 [[INDEX1]], 4
 ; CHECK-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
@@ -27,13 +25,13 @@ define i64 @early_exit_alignment_and_deref_known_via_assumption_with_constant_si
 ; CHECK:       middle.split:
 ; CHECK-NEXT:    br i1 [[TMP5]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
 ; CHECK:       middle.block:
-; CHECK-NEXT:    br i1 true, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; CHECK-NEXT:    br label [[LOOP_END:%.*]]
 ; CHECK:       vector.early.exit:
 ; CHECK-NEXT:    [[TMP8:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP4]], i1 true)
 ; CHECK-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX1]], [[TMP8]]
 ; CHECK-NEXT:    br label [[LOOP_END]]
 ; CHECK:       scalar.ph:
-; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 1024, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ]
 ; CHECK-NEXT:    br label [[LOOP1:%.*]]
 ; CHECK:       loop:
 ; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ [[INDEX_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]