| Dan Gohman | d2b62c4 | 2009-06-21 23:46:38 +0000 | [diff] [blame^] | 1 | ; RUN: llvm-as < %s | opt -analyze -scalar-evolution -disable-output \ |
| 2 | ; RUN: | grep {Loop bb: Unpredictable backedge-taken count\\.} |
| 3 | |
| 4 | ; ScalarEvolution can't compute a trip count because it doesn't know if |
| 5 | ; dividing by the stride will have a remainder. This could theoretically |
| 6 | ; be teaching it how to use a more elaborate trip count computation. |
| Nick Lewycky | c768d38 | 2008-11-18 15:10:54 +0000 | [diff] [blame] | 7 | |
| 8 | define i32 @f(i32 %x) nounwind readnone { |
| 9 | entry: |
| 10 | %0 = icmp ugt i32 %x, 4 ; <i1> [#uses=1] |
| 11 | br i1 %0, label %bb.nph, label %bb2 |
| 12 | |
| 13 | bb.nph: ; preds = %entry |
| 14 | br label %bb |
| 15 | |
| 16 | bb: ; preds = %bb.nph, %bb1 |
| 17 | %indvar = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb1 ] ; <i32> [#uses=2] |
| 18 | %tmp = mul i32 %indvar, -3 ; <i32> [#uses=1] |
| 19 | %x_addr.04 = add i32 %tmp, %x ; <i32> [#uses=1] |
| 20 | %1 = add i32 %x_addr.04, -3 ; <i32> [#uses=2] |
| 21 | br label %bb1 |
| 22 | |
| 23 | bb1: ; preds = %bb |
| 24 | %2 = icmp ugt i32 %1, 4 ; <i1> [#uses=1] |
| 25 | %indvar.next = add i32 %indvar, 1 ; <i32> [#uses=1] |
| 26 | br i1 %2, label %bb, label %bb1.bb2_crit_edge |
| 27 | |
| 28 | bb1.bb2_crit_edge: ; preds = %bb1 |
| 29 | %.lcssa = phi i32 [ %1, %bb1 ] ; <i32> [#uses=1] |
| 30 | br label %bb2 |
| 31 | |
| 32 | bb2: ; preds = %bb1.bb2_crit_edge, %entry |
| 33 | %x_addr.0.lcssa = phi i32 [ %.lcssa, %bb1.bb2_crit_edge ], [ %x, %entry ] ; <i32> [#uses=1] |
| 34 | ret i32 %x_addr.0.lcssa |
| 35 | } |