xref: /aosp_15_r20/external/llvm/test/Analysis/ScalarEvolution/2008-11-18-Stride1.ll (revision 9880d6810fe72a1726cb53787c6711e909410d58)
1*9880d681SAndroid Build Coastguard Worker; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
2*9880d681SAndroid Build Coastguard Worker
3*9880d681SAndroid Build Coastguard Worker; CHECK: Loop %bb: backedge-taken count is ((-5 + %x) /u 3)
4*9880d681SAndroid Build Coastguard Worker; CHECK: Loop %bb: max backedge-taken count is 1431655764
5*9880d681SAndroid Build Coastguard Worker
6*9880d681SAndroid Build Coastguard Worker
7*9880d681SAndroid Build Coastguard Worker; ScalarEvolution can't compute a trip count because it doesn't know if
8*9880d681SAndroid Build Coastguard Worker; dividing by the stride will have a remainder. This could theoretically
9*9880d681SAndroid Build Coastguard Worker; be teaching it how to use a more elaborate trip count computation.
10*9880d681SAndroid Build Coastguard Worker
11*9880d681SAndroid Build Coastguard Workerdefine i32 @f(i32 %x) nounwind readnone {
12*9880d681SAndroid Build Coastguard Workerentry:
13*9880d681SAndroid Build Coastguard Worker	%0 = icmp ugt i32 %x, 4		; <i1> [#uses=1]
14*9880d681SAndroid Build Coastguard Worker	br i1 %0, label %bb.nph, label %bb2
15*9880d681SAndroid Build Coastguard Worker
16*9880d681SAndroid Build Coastguard Workerbb.nph:		; preds = %entry
17*9880d681SAndroid Build Coastguard Worker	br label %bb
18*9880d681SAndroid Build Coastguard Worker
19*9880d681SAndroid Build Coastguard Workerbb:		; preds = %bb.nph, %bb1
20*9880d681SAndroid Build Coastguard Worker	%indvar = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb1 ]		; <i32> [#uses=2]
21*9880d681SAndroid Build Coastguard Worker	%tmp = mul i32 %indvar, -3		; <i32> [#uses=1]
22*9880d681SAndroid Build Coastguard Worker	%x_addr.04 = add i32 %tmp, %x		; <i32> [#uses=1]
23*9880d681SAndroid Build Coastguard Worker	%1 = add i32 %x_addr.04, -3		; <i32> [#uses=2]
24*9880d681SAndroid Build Coastguard Worker	br label %bb1
25*9880d681SAndroid Build Coastguard Worker
26*9880d681SAndroid Build Coastguard Workerbb1:		; preds = %bb
27*9880d681SAndroid Build Coastguard Worker	%2 = icmp ugt i32 %1, 4		; <i1> [#uses=1]
28*9880d681SAndroid Build Coastguard Worker	%indvar.next = add i32 %indvar, 1		; <i32> [#uses=1]
29*9880d681SAndroid Build Coastguard Worker	br i1 %2, label %bb, label %bb1.bb2_crit_edge
30*9880d681SAndroid Build Coastguard Worker
31*9880d681SAndroid Build Coastguard Workerbb1.bb2_crit_edge:		; preds = %bb1
32*9880d681SAndroid Build Coastguard Worker	%.lcssa = phi i32 [ %1, %bb1 ]		; <i32> [#uses=1]
33*9880d681SAndroid Build Coastguard Worker	br label %bb2
34*9880d681SAndroid Build Coastguard Worker
35*9880d681SAndroid Build Coastguard Workerbb2:		; preds = %bb1.bb2_crit_edge, %entry
36*9880d681SAndroid Build Coastguard Worker	%x_addr.0.lcssa = phi i32 [ %.lcssa, %bb1.bb2_crit_edge ], [ %x, %entry ]		; <i32> [#uses=1]
37*9880d681SAndroid Build Coastguard Worker	ret i32 %x_addr.0.lcssa
38*9880d681SAndroid Build Coastguard Worker}
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