| ; RUN: opt < %s -analyze -scalar-evolution \ |
| ; RUN: | grep "Loop %bb: Unpredictable backedge-taken count\." |
| |
| ; ScalarEvolution can't compute a trip count because it doesn't know if |
| ; dividing by the stride will have a remainder. This could theoretically |
| ; be teaching it how to use a more elaborate trip count computation. |
| |
| define i32 @f(i32 %x) nounwind readnone { |
| entry: |
| %0 = icmp ugt i32 %x, 4 ; <i1> [#uses=1] |
| br i1 %0, label %bb.nph, label %bb2 |
| |
| bb.nph: ; preds = %entry |
| br label %bb |
| |
| bb: ; preds = %bb.nph, %bb1 |
| %indvar = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb1 ] ; <i32> [#uses=2] |
| %tmp = mul i32 %indvar, -3 ; <i32> [#uses=1] |
| %x_addr.04 = add i32 %tmp, %x ; <i32> [#uses=1] |
| %1 = add i32 %x_addr.04, -3 ; <i32> [#uses=2] |
| br label %bb1 |
| |
| bb1: ; preds = %bb |
| %2 = icmp ugt i32 %1, 4 ; <i1> [#uses=1] |
| %indvar.next = add i32 %indvar, 1 ; <i32> [#uses=1] |
| br i1 %2, label %bb, label %bb1.bb2_crit_edge |
| |
| bb1.bb2_crit_edge: ; preds = %bb1 |
| %.lcssa = phi i32 [ %1, %bb1 ] ; <i32> [#uses=1] |
| br label %bb2 |
| |
| bb2: ; preds = %bb1.bb2_crit_edge, %entry |
| %x_addr.0.lcssa = phi i32 [ %.lcssa, %bb1.bb2_crit_edge ], [ %x, %entry ] ; <i32> [#uses=1] |
| ret i32 %x_addr.0.lcssa |
| } |
