1; This testcase is distilled from the GNU rx package. The loop should be 2; 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 -adce 15 16define i32 @rx_bitset_empty(i32 %size, i32* %set) { 17bb1: 18 %reg110 = load i32, i32* %set ; <i32> [#uses=2] 19 store i32 1, i32* %set 20 %cast112 = sext i32 %size to i64 ; <i64> [#uses=1] 21 %reg113 = add i64 %cast112, 31 ; <i64> [#uses=1] 22 %reg114 = lshr i64 %reg113, 5 ; <i64> [#uses=2] 23 %cast109 = trunc i64 %reg114 to i32 ; <i32> [#uses=1] 24 %reg129 = add i32 %cast109, -1 ; <i32> [#uses=1] 25 %reg114-idxcast = trunc i64 %reg114 to i32 ; <i32> [#uses=1] 26 %reg114-idxcast-offset = add i32 %reg114-idxcast, 1073741823 ; <i32> [#uses=1] 27 %reg114-idxcast-offset.upgrd.1 = zext i32 %reg114-idxcast-offset to i64 ; <i64> [#uses=1] 28 %reg124 = getelementptr i32, i32* %set, i64 %reg114-idxcast-offset.upgrd.1 ; <i32*> [#uses=1] 29 %reg125 = load i32, i32* %reg124 ; <i32> [#uses=1] 30 %cond232 = icmp ne i32 %reg125, 0 ; <i1> [#uses=1] 31 br i1 %cond232, label %bb3, label %bb2 32 33bb2: ; preds = %bb2, %bb1 34 %cann-indvar = phi i32 [ 0, %bb1 ], [ %add1-indvar, %bb2 ] ; <i32> [#uses=2] 35 %reg130-scale = mul i32 %cann-indvar, -1 ; <i32> [#uses=1] 36 %reg130 = add i32 %reg130-scale, %reg129 ; <i32> [#uses=1] 37 %add1-indvar = add i32 %cann-indvar, 1 ; <i32> [#uses=1] 38 %reg130-idxcast = bitcast i32 %reg130 to i32 ; <i32> [#uses=1] 39 %reg130-idxcast-offset = add i32 %reg130-idxcast, 1073741823 ; <i32> [#uses=1] 40 %reg130-idxcast-offset.upgrd.2 = zext i32 %reg130-idxcast-offset to i64 ; <i64> [#uses=1] 41 %reg118 = getelementptr i32, i32* %set, i64 %reg130-idxcast-offset.upgrd.2 ; <i32*> [#uses=1] 42 %reg119 = load i32, i32* %reg118 ; <i32> [#uses=1] 43 %cond233 = icmp eq i32 %reg119, 0 ; <i1> [#uses=1] 44 br i1 %cond233, label %bb2, label %bb3 45 46bb3: ; preds = %bb2, %bb1 47 store i32 %reg110, i32* %set 48 %cast126 = zext i32 %reg110 to i64 ; <i64> [#uses=1] 49 %reg127 = add i64 %cast126, -1 ; <i64> [#uses=1] 50 %reg128 = lshr i64 %reg127, 63 ; <i64> [#uses=1] 51 %cast120 = trunc i64 %reg128 to i32 ; <i32> [#uses=1] 52 ret i32 %cast120 53} 54 55