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1; This testcase is distilled from the GNU rx package. The loop should be2; removed but causes a problem when ADCE does. The source function is:3; int rx_bitset_empty (int size, rx_Bitset set) {4; int x;5; RX_subset s;6; s = set[0];7; set[0] = 1;8; for (x = rx_bitset_numb_subsets(size) - 1; !set[x]; --x)9; ;10; set[0] = s;11; return !s;12;}13;14; RUN: opt < %s -passes=adce15; RUN: opt < %s -passes=adce -adce-remove-loops -S | FileCheck %s16 17define i32 @rx_bitset_empty(i32 %size, ptr %set) {18bb1:19 %reg110 = load i32, ptr %set ; <i32> [#uses=2]20 store i32 1, ptr %set21 %cast112 = sext i32 %size to i64 ; <i64> [#uses=1]22 %reg113 = add i64 %cast112, 31 ; <i64> [#uses=1]23 %reg114 = lshr i64 %reg113, 5 ; <i64> [#uses=2]24 %cast109 = trunc i64 %reg114 to i32 ; <i32> [#uses=1]25 %reg129 = add i32 %cast109, -1 ; <i32> [#uses=1]26 %reg114-idxcast = trunc i64 %reg114 to i32 ; <i32> [#uses=1]27 %reg114-idxcast-offset = add i32 %reg114-idxcast, 1073741823 ; <i32> [#uses=1]28 %reg114-idxcast-offset.upgrd.1 = zext i32 %reg114-idxcast-offset to i64 ; <i64> [#uses=1]29 %reg124 = getelementptr i32, ptr %set, i64 %reg114-idxcast-offset.upgrd.1 ; <ptr> [#uses=1]30 %reg125 = load i32, ptr %reg124 ; <i32> [#uses=1]31 %cond232 = icmp ne i32 %reg125, 0 ; <i1> [#uses=1]32; CHECK: br label %bb333 br i1 %cond232, label %bb3, label %bb234 35bb2: ; preds = %bb2, %bb136 %cann-indvar = phi i32 [ 0, %bb1 ], [ %add1-indvar, %bb2 ] ; <i32> [#uses=2]37 %reg130-scale = mul i32 %cann-indvar, -1 ; <i32> [#uses=1]38 %reg130 = add i32 %reg130-scale, %reg129 ; <i32> [#uses=1]39 %add1-indvar = add i32 %cann-indvar, 1 ; <i32> [#uses=1]40 %reg130-idxcast = bitcast i32 %reg130 to i32 ; <i32> [#uses=1]41 %reg130-idxcast-offset = add i32 %reg130-idxcast, 1073741823 ; <i32> [#uses=1]42 %reg130-idxcast-offset.upgrd.2 = zext i32 %reg130-idxcast-offset to i64 ; <i64> [#uses=1]43 %reg118 = getelementptr i32, ptr %set, i64 %reg130-idxcast-offset.upgrd.2 ; <ptr> [#uses=1]44 %reg119 = load i32, ptr %reg118 ; <i32> [#uses=1]45 %cond233 = icmp eq i32 %reg119, 0 ; <i1> [#uses=1]46 br i1 %cond233, label %bb2, label %bb347 48bb3: ; preds = %bb2, %bb149 store i32 %reg110, ptr %set50 %cast126 = zext i32 %reg110 to i64 ; <i64> [#uses=1]51 %reg127 = add i64 %cast126, -1 ; <i64> [#uses=1]52 %reg128 = lshr i64 %reg127, 63 ; <i64> [#uses=1]53 %cast120 = trunc i64 %reg128 to i32 ; <i32> [#uses=1]54 ret i32 %cast12055}56 57