1 files changed, 49 insertions, 0 deletions
diff --git a/llvm/test/Transforms/LoopPredication/basic.ll b/llvm/test/Transforms/LoopPredication/basic.ll
index 95de26a5632..afb92f263cb 100644
--- a/llvm/test/Transforms/LoopPredication/basic.ll
+++ b/llvm/test/Transforms/LoopPredication/basic.ll
@@ -1544,3 +1544,52 @@ exit:
   %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
   ret i32 %result
 }
+
+
+; This is a case where the length information tells us that the guard
+; must trigger on some iteration.
+define i32 @provably_taken(i32* %array, i32* %length.ptr) {
+; CHECK-LABEL: @provably_taken(
+; CHECK-NEXT:  loop.preheader:
+; CHECK-NEXT:    [[LENGTH:%.*]] = load i32, i32* [[LENGTH_PTR:%.*]], !range !1
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp ult i32 0, [[LENGTH]]
+; CHECK-NEXT:    [[TMP1:%.*]] = and i1 [[TMP0]], false
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ]
+; CHECK-NEXT:    call void (i1, ...) @llvm.experimental.guard(i1 [[TMP1]], i32 9) [ "deopt"() ]
+; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
+; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
+; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
+; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
+; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
+; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp slt i32 [[I_NEXT]], 200
+; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[LOOP]] ]
+; CHECK-NEXT:    ret i32 [[RESULT]]
+;
+loop.preheader:
+  %length = load i32, i32* %length.ptr, !range !{i32 0, i32 50}
+  br label %loop
+
+loop:
+  %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
+  %i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
+  %within.bounds = icmp ult i32 %i, %length
+  call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
+
+  %i.i64 = zext i32 %i to i64
+  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
+  %array.i = load i32, i32* %array.i.ptr, align 4
+  %loop.acc.next = add i32 %loop.acc, %array.i
+
+  %i.next = add nuw i32 %i, 1
+  %continue = icmp slt i32 %i.next, 200
+  br i1 %continue, label %loop, label %exit
+
+exit:
+  %result = phi i32 [ %loop.acc.next, %loop ]
+  ret i32 %result
+}