[LoopIdiom] BCmp: check, not assert that loop exits exit out of the loop (PR43687)

We can't normally stumble into that assertion because a tautological
*conditional* `br` in loop body is required, one that always
branches to loop latch. But that should have been always folded
to an unconditional branch before we get it.
But that is not guaranteed if the pass is run standalone.
So let's just promote the assertion into a proper check.

Fixes https://bugs.llvm.org/show_bug.cgi?id=43687

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375100 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 917d1119dc68b7362294ad3a2ef6e23e5222ea42..dd477e8006937606f519e5ba11aa657d10c54333 100644 (file)
--- a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -1968,21 +1968,22 @@ bool LoopIdiomRecognize::recognizeBCmpLoopControlFlow(
   if (CmpLoop.LatchBrContinueBB != LoopHeaderBB)
     std::swap(CmpLoop.LatchBrFinishBB, CmpLoop.LatchBrContinueBB);
 
+  SmallVector<BasicBlock *, 2> ExitBlocks;
+
+  CurLoop->getUniqueExitBlocks(ExitBlocks);
+  assert(ExitBlocks.size() <= 2U && "Can't have more than two exit blocks.");
+
   // Check that control-flow between blocks is as expected.
   if (CmpLoop.HeaderBrEqualBB != LoopLatchBB ||
-      CmpLoop.LatchBrContinueBB != LoopHeaderBB) {
+      CmpLoop.LatchBrContinueBB != LoopHeaderBB ||
+      !is_contained(ExitBlocks, CmpLoop.HeaderBrUnequalBB) ||
+      !is_contained(ExitBlocks, CmpLoop.LatchBrFinishBB)) {
     LLVM_DEBUG(dbgs() << "Loop control-flow not recognized.\n");
     return false;
   }
 
-  SmallVector<BasicBlock *, 2> ExitBlocks;
-  CurLoop->getUniqueExitBlocks(ExitBlocks);
-  assert(ExitBlocks.size() <= 2U && "Can't have more than two exit blocks.");
-
   assert(!is_contained(ExitBlocks, CmpLoop.HeaderBrEqualBB) &&
-         is_contained(ExitBlocks, CmpLoop.HeaderBrUnequalBB) &&
          !is_contained(ExitBlocks, CmpLoop.LatchBrContinueBB) &&
-         is_contained(ExitBlocks, CmpLoop.LatchBrFinishBB) &&
          "Unexpected exit edges.");
 
   LLVM_DEBUG(dbgs() << "Recognized loop control-flow.\n");

diff --git a/test/Transforms/LoopIdiom/bcmp-negative-tests.ll b/test/Transforms/LoopIdiom/bcmp-negative-tests.ll
index a4d4a3d250ae633d96aea883b8acee06dc5a74ea..e35821bfb0122ed306cf3e00c3a25e367a508eb6 100644 (file)
--- a/test/Transforms/LoopIdiom/bcmp-negative-tests.ll
+++ b/test/Transforms/LoopIdiom/bcmp-negative-tests.ll
@@ -6,6 +6,30 @@
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 
 define i1 @three_blocks_and_two_latches_in_loop(i8* %ptr0, i8* %ptr1) {
+; CHECK-LABEL: @three_blocks_and_two_latches_in_loop(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[I_08_BE:%.*]], [[FOR_BODY_BACKEDGE:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC:%.*]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_PASSTHROUGH:%.*]], label [[CLEANUP:%.*]]
+; CHECK:       for.passthrough:
+; CHECK-NEXT:    br i1 true, label [[FOR_COND:%.*]], label [[FOR_BODY_BACKEDGE]]
+; CHECK:       for.body.backedge:
+; CHECK-NEXT:    [[I_08_BE]] = phi i64 [ [[INC]], [[FOR_COND]] ], [ 0, [[FOR_PASSTHROUGH]] ]
+; CHECK-NEXT:    br label [[FOR_BODY]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY_BACKEDGE]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -32,6 +56,27 @@ cleanup:
 }
 
 define i1 @three_blocks_in_loop(i8* %ptr0, i8* %ptr1) {
+; CHECK-LABEL: @three_blocks_in_loop(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_PASSTHROUGH:%.*]], label [[CLEANUP:%.*]]
+; CHECK:       for.passthrough:
+; CHECK-NEXT:    br label [[FOR_COND]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -58,6 +103,25 @@ cleanup:
 }
 
 define i1 @body_cmp_is_not_equality(i8* %ptr0, i8* %ptr1) {
+; CHECK-LABEL: @body_cmp_is_not_equality(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp ult i8 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -81,6 +145,23 @@ cleanup:
 }
 
 define i1 @only_one_load(i8* %ptr0, i8* %ptr1) {
+; CHECK-LABEL: @only_one_load(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], 0
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -102,6 +183,25 @@ cleanup:
 }
 
 define i1 @loads_of_less_than_byte(i7* %ptr0, i7* %ptr1) {
+; CHECK-LABEL: @loads_of_less_than_byte(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i7, i7* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i7, i7* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i7, i7* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i7, i7* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp ult i7 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -125,6 +225,25 @@ cleanup:
 }
 
 define i1 @loads_of_not_multiple_of_a_byte(i9* %ptr0, i9* %ptr1) {
+; CHECK-LABEL: @loads_of_not_multiple_of_a_byte(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i9, i9* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i9, i9* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i9, i9* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i9, i9* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp ult i9 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -148,6 +267,25 @@ cleanup:
 }
 
 define i1 @loop_instruction_used_in_phi_node_outside_loop(i8* %ptr0, i8* %ptr1) {
+; CHECK-LABEL: @loop_instruction_used_in_phi_node_outside_loop(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ [[CMP3]], [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -171,6 +309,26 @@ cleanup:
 }
 
 define i1 @loop_has_write(i8* %ptr0, i8* %ptr1, i32* %write) {
+; CHECK-LABEL: @loop_has_write(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    store i32 0, i32* [[WRITE:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -196,6 +354,26 @@ cleanup:
 
 declare void @sink()
 define i1 @loop_has_call(i8* %ptr0, i8* %ptr1, i32* %load) {
+; CHECK-LABEL: @loop_has_call(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    tail call void @sink()
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -220,6 +398,26 @@ cleanup:
 }
 
 define i1 @loop_has_atomic_load(i8* %ptr0, i8* %ptr1, i32* %load) {
+; CHECK-LABEL: @loop_has_atomic_load(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_08:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_COND:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, i8* [[PTR0:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[ARRAYIDX]]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, i8* [[PTR1:%.*]], i64 [[I_08]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[ARRAYIDX1]]
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_08]], 1
+; CHECK-NEXT:    br i1 [[CMP3]], label [[FOR_COND]], label [[CLEANUP:%.*]]
+; CHECK:       for.cond:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 8
+; CHECK-NEXT:    [[TMP:%.*]] = load atomic i32, i32* [[LOAD:%.*]] unordered, align 1
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_COND]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   br label %for.body
 
@@ -244,6 +442,28 @@ cleanup:
 }
 
 define i1 @different_load_step(i8* %ptr) {
+; CHECK-LABEL: @different_load_step(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_015:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_014:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_013:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[INCDEC_PTR:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[PTR0_013]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[PTR1_014]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_015]], 1
+; CHECK-NEXT:    [[INCDEC_PTR]] = getelementptr inbounds i8, i8* [[PTR0_013]], i64 1
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR1_014]], i64 2
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -270,6 +490,28 @@ cleanup:
 }
 
 define i1 @step_is_variable(i8* %ptr, i64 %step) {
+; CHECK-LABEL: @step_is_variable(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_015:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_014:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_013:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[INCDEC_PTR:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[PTR0_013]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[PTR1_014]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_015]], [[STEP:%.*]]
+; CHECK-NEXT:    [[INCDEC_PTR]] = getelementptr inbounds i8, i8* [[PTR0_013]], i64 1
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR1_014]], i64 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -296,6 +538,28 @@ cleanup:
 }
 
 define i1 @load_step_is_variable(i8* %ptr, i64 %step) {
+; CHECK-LABEL: @load_step_is_variable(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_015:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_014:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_013:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[INCDEC_PTR:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[PTR0_013]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[PTR1_014]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_015]], 1
+; CHECK-NEXT:    [[INCDEC_PTR]] = getelementptr inbounds i8, i8* [[PTR0_013]], i64 [[STEP:%.*]]
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR1_014]], i64 [[STEP]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -322,6 +586,28 @@ cleanup:
 }
 
 define i1 @step_and_load_step_is_variable(i8* %ptr, i64 %step) {
+; CHECK-LABEL: @step_and_load_step_is_variable(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_015:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_014:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_013:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[INCDEC_PTR:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[PTR0_013]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[PTR1_014]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_015]], [[STEP:%.*]]
+; CHECK-NEXT:    [[INCDEC_PTR]] = getelementptr inbounds i8, i8* [[PTR0_013]], i64 [[STEP]]
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR1_014]], i64 [[STEP]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -348,6 +634,28 @@ cleanup:
 }
 
 define i1 @load_step_not_affine(i8* %ptr) {
+; CHECK-LABEL: @load_step_not_affine(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_018:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_017:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR4:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_016:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[PTR0_016]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[PTR1_017]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_018]], 1
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR0_016]], i64 [[INC]]
+; CHECK-NEXT:    [[ADD_PTR4]] = getelementptr inbounds i8, i8* [[PTR1_017]], i64 [[INC]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -374,6 +682,28 @@ cleanup:
 }
 
 define i1 @no_overlap_between_loads(i8* %ptr) {
+; CHECK-LABEL: @no_overlap_between_loads(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_016:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_015:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR4:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_014:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8* [[PTR0_014]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8* [[PTR1_015]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_016]], 1
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR0_014]], i64 2
+; CHECK-NEXT:    [[ADD_PTR4]] = getelementptr inbounds i8, i8* [[PTR1_015]], i64 2
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -400,6 +730,28 @@ cleanup:
 }
 
 define i1 @volatile_loads(i8* %ptr) {
+; CHECK-LABEL: @volatile_loads(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_016:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_015:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR4:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_014:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load volatile i8, i8* [[PTR0_014]]
+; CHECK-NEXT:    [[V1:%.*]] = load volatile i8, i8* [[PTR1_015]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_016]], 1
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR0_014]], i64 1
+; CHECK-NEXT:    [[ADD_PTR4]] = getelementptr inbounds i8, i8* [[PTR1_015]], i64 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -426,6 +778,28 @@ cleanup:
 }
 
 define i1 @atomic_loads(i8* %ptr) {
+; CHECK-LABEL: @atomic_loads(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_016:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_015:%.*]] = phi i8* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR4:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_014:%.*]] = phi i8* [ [[PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load atomic i8, i8* [[PTR0_014]] unordered, align 1
+; CHECK-NEXT:    [[V1:%.*]] = load atomic i8, i8* [[PTR1_015]] unordered, align 1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_016]], 1
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8* [[PTR0_014]], i64 1
+; CHECK-NEXT:    [[ADD_PTR4]] = getelementptr inbounds i8, i8* [[PTR1_015]], i64 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8* %ptr, i64 8
   br label %for.body
@@ -452,6 +826,28 @@ cleanup:
 }
 
 define i1 @address_space(i8 addrspace(1)* %ptr) {
+; CHECK-LABEL: @address_space(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, i8 addrspace(1)* [[PTR:%.*]], i64 8
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_016:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT:    [[PTR1_015:%.*]] = phi i8 addrspace(1)* [ [[ADD_PTR]], [[ENTRY]] ], [ [[ADD_PTR4:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[PTR0_014:%.*]] = phi i8 addrspace(1)* [ [[PTR]], [[ENTRY]] ], [ [[ADD_PTR3:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT:    [[V0:%.*]] = load i8, i8 addrspace(1)* [[PTR0_014]]
+; CHECK-NEXT:    [[V1:%.*]] = load i8, i8 addrspace(1)* [[PTR1_015]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i8 [[V0]], [[V1]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[FOR_INC]], label [[CLEANUP:%.*]]
+; CHECK:       for.inc:
+; CHECK-NEXT:    [[INC]] = add nuw nsw i64 [[I_016]], 1
+; CHECK-NEXT:    [[ADD_PTR3]] = getelementptr inbounds i8, i8 addrspace(1)* [[PTR0_014]], i64 1
+; CHECK-NEXT:    [[ADD_PTR4]] = getelementptr inbounds i8, i8 addrspace(1)* [[PTR1_015]], i64 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[INC]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    [[RES:%.*]] = phi i1 [ false, [[FOR_BODY]] ], [ true, [[FOR_INC]] ]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
 entry:
   %add.ptr = getelementptr inbounds i8, i8 addrspace(1)* %ptr, i64 8
   br label %for.body
@@ -489,6 +885,45 @@ cleanup:
 ; The loads proceed differently here - fillch[i] changes once per outer loop,
 ; while bptr[i][j] changes both in inner loop, and in outer loop.
 define i1 @pr43206_different_loops(i32 %i_max, i32 %j_max, i32** %bptr, i32* %fillch) {
+; CHECK-LABEL: @pr43206_different_loops(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP31:%.*]] = icmp sgt i32 [[I_MAX:%.*]], 0
+; CHECK-NEXT:    [[CMP229:%.*]] = icmp sgt i32 [[J_MAX:%.*]], 0
+; CHECK-NEXT:    [[OR_COND:%.*]] = and i1 [[CMP31]], [[CMP229]]
+; CHECK-NEXT:    br i1 [[OR_COND]], label [[FOR_COND1_PREHEADER_US_PREHEADER:%.*]], label [[CLEANUP12:%.*]]
+; CHECK:       for.cond1.preheader.us.preheader:
+; CHECK-NEXT:    [[WIDE_TRIP_COUNT38:%.*]] = zext i32 [[I_MAX]] to i64
+; CHECK-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[J_MAX]] to i64
+; CHECK-NEXT:    br label [[FOR_COND1_PREHEADER_US:%.*]]
+; CHECK:       for.cond1.preheader.us:
+; CHECK-NEXT:    [[INDVARS_IV36:%.*]] = phi i64 [ 0, [[FOR_COND1_PREHEADER_US_PREHEADER]] ], [ [[INDVARS_IV_NEXT37:%.*]], [[FOR_COND1_FOR_INC10_CRIT_EDGE_US:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX_US:%.*]] = getelementptr inbounds i32*, i32** [[BPTR:%.*]], i64 [[INDVARS_IV36]]
+; CHECK-NEXT:    [[V0:%.*]] = load i32*, i32** [[ARRAYIDX_US]], align 8
+; CHECK-NEXT:    [[ARRAYIDX8_US:%.*]] = getelementptr inbounds i32, i32* [[FILLCH:%.*]], i64 [[INDVARS_IV36]]
+; CHECK-NEXT:    [[V1:%.*]] = load i32, i32* [[ARRAYIDX8_US]], align 4
+; CHECK-NEXT:    br label [[FOR_BODY4_US:%.*]]
+; CHECK:       for.cond1.us:
+; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT:%.*]], [[WIDE_TRIP_COUNT]]
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[FOR_COND1_FOR_INC10_CRIT_EDGE_US]], label [[FOR_BODY4_US]]
+; CHECK:       for.body4.us:
+; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ 0, [[FOR_COND1_PREHEADER_US]] ], [ [[INDVARS_IV_NEXT]], [[FOR_COND1_US:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX6_US:%.*]] = getelementptr inbounds i32, i32* [[V0]], i64 [[INDVARS_IV]]
+; CHECK-NEXT:    [[V2:%.*]] = load i32, i32* [[ARRAYIDX6_US]], align 4
+; CHECK-NEXT:    [[CMP9_US:%.*]] = icmp eq i32 [[V2]], [[V1]]
+; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
+; CHECK-NEXT:    br i1 [[CMP9_US]], label [[FOR_COND1_US]], label [[CLEANUP12_LOOPEXIT:%.*]]
+; CHECK:       for.cond1.for.inc10_crit_edge.us:
+; CHECK-NEXT:    [[INDVARS_IV_NEXT37]] = add nuw nsw i64 [[INDVARS_IV36]], 1
+; CHECK-NEXT:    [[EXITCOND39:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT37]], [[WIDE_TRIP_COUNT38]]
+; CHECK-NEXT:    br i1 [[EXITCOND39]], label [[CLEANUP12_LOOPEXIT1:%.*]], label [[FOR_COND1_PREHEADER_US]]
+; CHECK:       cleanup12.loopexit:
+; CHECK-NEXT:    br label [[CLEANUP12]]
+; CHECK:       cleanup12.loopexit1:
+; CHECK-NEXT:    br label [[CLEANUP12]]
+; CHECK:       cleanup12:
+; CHECK-NEXT:    [[V3:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ true, [[CLEANUP12_LOOPEXIT]] ], [ false, [[CLEANUP12_LOOPEXIT1]] ]
+; CHECK-NEXT:    ret i1 [[V3]]
+;
 entry:
   %cmp31 = icmp sgt i32 %i_max, 0
   %cmp229 = icmp sgt i32 %j_max, 0
@@ -529,3 +964,36 @@ cleanup12:                                        ; preds = %for.cond1.for.inc10
   %v3 = phi i1 [ false, %entry ], [ true, %for.body4.us ], [ false, %for.cond1.for.inc10_crit_edge.us ]
   ret i1 %v3
 }
+
+; From https://bugs.llvm.org/show_bug.cgi?id=43687
+define void @body_always_branches_to_latch(i16* %a, i16* %b, i32) {
+; CHECK-LABEL: @body_always_branches_to_latch(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    [[A_DATA:%.*]] = load i16, i16* [[A:%.*]]
+; CHECK-NEXT:    [[B_DATA:%.*]] = load i16, i16* [[B:%.*]]
+; CHECK-NEXT:    [[COMPARED_EQUAL:%.*]] = icmp eq i16 [[A_DATA]], [[B_DATA]]
+; CHECK-NEXT:    br i1 [[COMPARED_EQUAL]], label [[LATCH:%.*]], label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    [[SHOULD_CONTINUE:%.*]] = icmp slt i32 undef, 79
+; CHECK-NEXT:    br i1 [[SHOULD_CONTINUE]], label [[BODY]], label [[END:%.*]]
+; CHECK:       end:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %body
+
+body:                                   ; preds = %latch, %for.end1317
+  %a_data = load i16, i16* %a
+  %b_data = load i16, i16* %b
+  %compared_equal = icmp eq i16 %a_data, %b_data
+  br i1 %compared_equal, label %latch, label %latch
+
+latch:                                    ; preds = %body, %body
+  %should_continue = icmp slt i32 undef, 79
+  br i1 %should_continue, label %body, label %end
+
+end:                                    ; preds = %latch
+  ret void
+}