xref: /aosp_15_r20/external/llvm/test/Transforms/JumpThreading/degenerate-phi.ll (revision 9880d6810fe72a1726cb53787c6711e909410d58)
1*9880d681SAndroid Build Coastguard Worker; RUN: opt -jump-threading -disable-output < %s
2*9880d681SAndroid Build Coastguard Worker; PR9112
3*9880d681SAndroid Build Coastguard Worker
4*9880d681SAndroid Build Coastguard Worker; This is actually a test for value tracking. Jump threading produces
5*9880d681SAndroid Build Coastguard Worker; "%phi = phi i16" when it removes all edges leading to %unreachable.
6*9880d681SAndroid Build Coastguard Worker; The .ll parser won't let us write that directly since it's invalid code.
7*9880d681SAndroid Build Coastguard Worker
8*9880d681SAndroid Build Coastguard Workerdefine void @func() nounwind {
9*9880d681SAndroid Build Coastguard Workerentry:
10*9880d681SAndroid Build Coastguard Worker  br label %bb
11*9880d681SAndroid Build Coastguard Worker
12*9880d681SAndroid Build Coastguard Workerbb:
13*9880d681SAndroid Build Coastguard Worker  br label %bb
14*9880d681SAndroid Build Coastguard Worker
15*9880d681SAndroid Build Coastguard Workerunreachable:
16*9880d681SAndroid Build Coastguard Worker  %phi = phi i16 [ %add, %unreachable ], [ 0, %next ]
17*9880d681SAndroid Build Coastguard Worker  %add = add i16 0, %phi
18*9880d681SAndroid Build Coastguard Worker  %cmp = icmp slt i16 %phi, 0
19*9880d681SAndroid Build Coastguard Worker  br i1 %cmp, label %unreachable, label %next
20*9880d681SAndroid Build Coastguard Worker
21*9880d681SAndroid Build Coastguard Workernext:
22*9880d681SAndroid Build Coastguard Worker  br label %unreachable
23*9880d681SAndroid Build Coastguard Worker}
24*9880d681SAndroid Build Coastguard Worker
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