36 lines
1.2 KiB
LLVM
36 lines
1.2 KiB
LLVM
; 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
|
|
}
|