xref: /llvm-project/llvm/test/CodeGen/AArch64/flags-multiuse.ll (revision db158c7c830807caeeb0691739c41f1d522029e9)
1; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 2
2; RUN: llc -mtriple=aarch64-none-linux-gnu -aarch64-enable-atomic-cfg-tidy=0 -verify-machineinstrs -o - %s | FileCheck %s
3
4; LLVM should be able to cope with multiple uses of the same flag-setting
5; instruction at different points of a routine. Either by rematerializing the
6; compare or by saving and restoring the flag register.
7
8declare void @bar()
9
10@var = global i32 0
11
12define i32 @test_multiflag(i32 %n, i32 %m, i32 %o) {
13; CHECK-LABEL: test_multiflag:
14; CHECK:       // %bb.0:
15; CHECK-NEXT:    str x30, [sp, #-32]! // 8-byte Folded Spill
16; CHECK-NEXT:    stp x20, x19, [sp, #16] // 16-byte Folded Spill
17; CHECK-NEXT:    .cfi_def_cfa_offset 32
18; CHECK-NEXT:    .cfi_offset w19, -8
19; CHECK-NEXT:    .cfi_offset w20, -16
20; CHECK-NEXT:    .cfi_offset w30, -32
21; CHECK-NEXT:    adrp x8, :got:var
22; CHECK-NEXT:    cmp w0, w1
23; CHECK-NEXT:    mov w19, w1
24; CHECK-NEXT:    ldr x8, [x8, :got_lo12:var]
25; CHECK-NEXT:    cset w9, ne
26; CHECK-NEXT:    mov w20, w0
27; CHECK-NEXT:    str w9, [x8]
28; CHECK-NEXT:    bl bar
29; CHECK-NEXT:    cmp w20, w19
30; CHECK-NEXT:    b.eq .LBB0_2
31; CHECK-NEXT:  // %bb.1: // %iftrue
32; CHECK-NEXT:    mov w0, #42 // =0x2a
33; CHECK-NEXT:    b .LBB0_3
34; CHECK-NEXT:  .LBB0_2: // %iffalse
35; CHECK-NEXT:    mov w0, wzr
36; CHECK-NEXT:  .LBB0_3: // %iftrue
37; CHECK-NEXT:    ldp x20, x19, [sp, #16] // 16-byte Folded Reload
38; CHECK-NEXT:    ldr x30, [sp], #32 // 8-byte Folded Reload
39; CHECK-NEXT:    ret
40
41  %test = icmp ne i32 %n, %m
42
43  %val = zext i1 %test to i32
44
45
46  store i32 %val, ptr @var
47
48  call void @bar()
49
50  ; Currently, the comparison is emitted again. An MSR/MRS pair would also be
51  ; acceptable, but assuming the call preserves NZCV is not.
52  br i1 %test, label %iftrue, label %iffalse
53
54iftrue:
55  ret i32 42
56iffalse:
57  ret i32 0
58}
59