xref: /aosp_15_r20/external/llvm/test/CodeGen/AArch64/optimize-cond-branch.ll (revision 9880d6810fe72a1726cb53787c6711e909410d58)
1*9880d681SAndroid Build Coastguard Worker; RUN: llc -verify-machineinstrs -o - %s | FileCheck %s
2*9880d681SAndroid Build Coastguard Workertarget triple = "arm64--"
3*9880d681SAndroid Build Coastguard Worker
4*9880d681SAndroid Build Coastguard Worker; AArch64InstrInfo::optimizeCondBranch() optimizes the
5*9880d681SAndroid Build Coastguard Worker; "x = and y, 256; cmp x, 0; br" from an "and; cbnz" to a tbnz instruction.
6*9880d681SAndroid Build Coastguard Worker; It forgot to clear the a flag resulting in a MachineVerifier complaint.
7*9880d681SAndroid Build Coastguard Worker;
8*9880d681SAndroid Build Coastguard Worker; Writing a stable/simple test is tricky since most tbz instructions are already
9*9880d681SAndroid Build Coastguard Worker; formed in SelectionDAG, optimizeCondBranch() only triggers if the and
10*9880d681SAndroid Build Coastguard Worker; instruction is in a different block than the conditional jump.
11*9880d681SAndroid Build Coastguard Worker;
12*9880d681SAndroid Build Coastguard Worker; CHECK-LABEL: func
13*9880d681SAndroid Build Coastguard Worker; CHECK-NOT: and
14*9880d681SAndroid Build Coastguard Worker; CHECK: tbnz
15*9880d681SAndroid Build Coastguard Workerdefine void @func() {
16*9880d681SAndroid Build Coastguard Worker  %c0 = icmp sgt i64 0, 0
17*9880d681SAndroid Build Coastguard Worker  br i1 %c0, label %b1, label %b6
18*9880d681SAndroid Build Coastguard Worker
19*9880d681SAndroid Build Coastguard Workerb1:
20*9880d681SAndroid Build Coastguard Worker  br i1 undef, label %b3, label %b2
21*9880d681SAndroid Build Coastguard Worker
22*9880d681SAndroid Build Coastguard Workerb2:
23*9880d681SAndroid Build Coastguard Worker  %v0 = tail call i32 @extfunc()
24*9880d681SAndroid Build Coastguard Worker  br label %b5
25*9880d681SAndroid Build Coastguard Worker
26*9880d681SAndroid Build Coastguard Workerb3:
27*9880d681SAndroid Build Coastguard Worker  %v1 = load i32, i32* undef, align 4
28*9880d681SAndroid Build Coastguard Worker  %v2 = and i32 %v1, 256
29*9880d681SAndroid Build Coastguard Worker  br label %b5
30*9880d681SAndroid Build Coastguard Worker
31*9880d681SAndroid Build Coastguard Workerb5:
32*9880d681SAndroid Build Coastguard Worker  %v3 = phi i32 [ %v2, %b3 ], [ %v0, %b2 ]
33*9880d681SAndroid Build Coastguard Worker  %c1 = icmp eq i32 %v3, 0
34*9880d681SAndroid Build Coastguard Worker  br i1 %c1, label %b8, label %b7
35*9880d681SAndroid Build Coastguard Worker
36*9880d681SAndroid Build Coastguard Workerb6:
37*9880d681SAndroid Build Coastguard Worker  tail call i32 @extfunc()
38*9880d681SAndroid Build Coastguard Worker  ret void
39*9880d681SAndroid Build Coastguard Worker
40*9880d681SAndroid Build Coastguard Workerb7:
41*9880d681SAndroid Build Coastguard Worker  tail call i32 @extfunc()
42*9880d681SAndroid Build Coastguard Worker  ret void
43*9880d681SAndroid Build Coastguard Worker
44*9880d681SAndroid Build Coastguard Workerb8:
45*9880d681SAndroid Build Coastguard Worker  ret void
46*9880d681SAndroid Build Coastguard Worker}
47*9880d681SAndroid Build Coastguard Worker
48*9880d681SAndroid Build Coastguard Workerdeclare i32 @extfunc()
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