[LV] Amend check for IV increments in collectUsersInEntryBlock

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -8662,6 +8662,7 @@ static MapVector<PHINode *, VPValue *> collectUsersInExitBlock(
          !cast<VPWidenIntOrFpInductionRecipe>(V)->getTruncInst()) ||
         isa<VPWidenPointerInductionRecipe>(V) ||
         (isa<Instruction>(IncomingValue) &&
+         OrigLoop->contains(cast<Instruction>(IncomingValue)) &&
          any_of(IncomingValue->users(), [&Inductions](User *U) {
            auto *P = dyn_cast<PHINode>(U);
            return P && Inductions.contains(P);

llvm/test/Transforms/LoopVectorize/use-iv-start-value.ll

@@ -0,0 +1,74 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes=loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -S | FileCheck %s
+
+; Check that we correctly handle the use of %start2 in the exit block, and do
+; not crash.
+
+define i64 @foo(ptr %p1, ptr %p2, i64 %start, i64 %end) {
+; CHECK-LABEL: define i64 @foo(
+; CHECK-SAME: ptr [[P1:%.*]], ptr [[P2:%.*]], i64 [[START:%.*]], i64 [[END:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[START2:%.*]] = and i64 [[START]], 12345
+; CHECK-NEXT:    [[TMP0:%.*]] = sub i64 [[END]], [[START2]]
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP0]], 4
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP0]], 4
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP0]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[IND_END:%.*]] = add i64 [[START2]], [[N_VEC]]
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i64 [[START2]], [[INDEX]]
+; CHECK-NEXT:    [[IND:%.*]] = add i64 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i32, ptr [[P1]], i64 [[IND]]
+; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[ARRAYIDX1]], i32 0
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i32, ptr [[P2]], i64 [[IND]]
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i32, ptr [[TMP4]], i32 0
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP0]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[IND_END]], %[[MIDDLE_BLOCK]] ], [ [[START2]], %[[ENTRY]] ]
+; CHECK-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK:       [[FOR_BODY]]:
+; CHECK-NEXT:    [[IND1:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IND_NEXT1:%.*]], %[[FOR_BODY]] ]
+; CHECK-NEXT:    [[ARRAYIDX3:%.*]] = getelementptr inbounds i32, ptr [[P1]], i64 [[IND1]]
+; CHECK-NEXT:    [[TMP7:%.*]] = load i32, ptr [[ARRAYIDX3]], align 4
+; CHECK-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[P2]], i64 [[IND1]]
+; CHECK-NEXT:    [[TMP8:%.*]] = load i32, ptr [[ARRAYIDX2]], align 4
+; CHECK-NEXT:    [[IND_NEXT1]] = add i64 [[IND1]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IND_NEXT1]], [[END]]
+; CHECK-NEXT:    br i1 [[CMP]], label %[[FOR_BODY]], label %[[EXIT]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    [[USE:%.*]] = phi i64 [ [[START2]], %[[FOR_BODY]] ], [ [[START2]], %[[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i64 [[USE]]
+;
+entry:
+  %start2 = and i64 %start, 12345
+  br label %for.body
+
+for.body:
+  %ind = phi i64 [ %start2, %entry ], [ %ind.next, %for.body ]
+  %arrayidx1 = getelementptr inbounds i32, ptr %p1, i64 %ind
+  %0 = load i32, ptr %arrayidx1, align 4
+  %arrayidx2 = getelementptr inbounds i32, ptr %p2, i64 %ind
+  %1 = load i32, ptr %arrayidx2, align 4
+  %ind.next = add i64 %ind, 1
+  %cmp = icmp ne i64 %ind.next, %end
+  br i1 %cmp, label %for.body, label %exit
+
+exit:
+  %use =  phi i64 [ %start2, %for.body ]
+  ret i64 %use
+}
+
+;.
+; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
+; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
+; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META2]], [[META1]]}
+;.