xref: /llvm-project/bolt/test/AArch64/double_jump.cpp (revision 003b48e0cbbb69a9a1ca9ff1a6d3bda30d0c6121)
1 // A contrived example to test the double jump removal peephole.
2 
3 // RUN: %clangxx %cxxflags -O0 %s -o %t.exe
4 // RUN: llvm-bolt %t.exe -o %t.bolt --peepholes=double-jumps | \
5 // RUN:   FileCheck %s -check-prefix=CHECKBOLT
6 // RUN: llvm-objdump --no-print-imm-hex -d %t.bolt | FileCheck %s
7 
8 // CHECKBOLT: BOLT-INFO: Peephole: 1 double jumps patched.
9 
10 // CHECK: <_Z3foom>:
11 // CHECK-NEXT: sub     sp, sp, #16
12 // CHECK-NEXT: str     x0, [sp, #8]
13 // CHECK-NEXT: ldr     [[REG:x[0-28]+]], [sp, #8]
14 // CHECK-NEXT: cmp     [[REG]], #0
15 // CHECK-NEXT: b.eq    {{.*}} <_Z3foom+0x34>
16 // CHECK-NEXT: add     [[REG]], [[REG]], #1
17 // CHECK-NEXT: add     [[REG]], [[REG]], #1
18 // CHECK-NEXT: cmp     [[REG]], #2
19 // CHECK-NEXT: b.eq    {{.*}} <_Z3foom+0x28>
20 // CHECK-NEXT: add     [[REG]], [[REG]], #1
21 // CHECK-NEXT: mov     [[REG]], x1
22 // CHECK-NEXT: ldr     x1, [sp]
23 // CHECK-NEXT: b       {{.*}} <bar>
24 // CHECK-NEXT: ldr     x1, [sp]
25 // CHECK-NEXT: add     [[REG]], [[REG]], #1
26 // CHECK-NEXT: b       {{.*}} <bar>
27 
28 extern "C" unsigned long bar(unsigned long count) { return count + 1; }
29 
30 unsigned long foo(unsigned long count) {
31   asm volatile("     cmp %0,#0\n"
32                "     b.eq .L7\n"
33                "     add %0, %0, #1\n"
34                "     b .L1\n"
35                ".L1: b .L2\n"
36                ".L2: add  %0, %0, #1\n"
37                "     cmp  %0, #2\n"
38                "     b.ne .L3\n"
39                "     b .L4\n"
40                ".L3: b .L5\n"
41                ".L5: add %0, %0, #1\n"
42                ".L4: mov %0,x1\n"
43                "     ldr x1, [sp]\n"
44                "     b .L6\n"
45                ".L7: ldr x1, [sp]\n"
46                "     add %0, %0, #1\n"
47                "     b .L6\n"
48                ".L6: b bar\n"
49                :
50                : "r"(count)
51                :);
52   return count;
53 }
54 
55 extern "C" int _start() { return foo(38); }
56