1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -o - %s -mtriple=x86_64-- | FileCheck %s
; Example of a decref operation with "immortal" objects.
; void decref(long* refcount) {
; long count = *refcount;
; if (count == 1) { free_object() }
; else if (count > 1) { *refcount = count - 1; }
; else { /* immortal */ }
; }
; Resulting assembly should share flags from single CMP instruction for both
; conditions!
define void @decref(ptr %p) {
; CHECK-LABEL: decref:
; CHECK: # %bb.0:
; CHECK-NEXT: movl (%rdi), %eax
; CHECK-NEXT: cmpl $1, %eax
; CHECK-NEXT: jne .LBB0_2
; CHECK-NEXT: # %bb.1: # %bb_free
; CHECK-NEXT: pushq %rax
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: callq free_object@PLT
; CHECK-NEXT: addq $8, %rsp
; CHECK-NEXT: .cfi_def_cfa_offset 8
; CHECK-NEXT: .LBB0_4: # %end
; CHECK-NEXT: retq
; CHECK-NEXT: .LBB0_2: # %bb2
; CHECK-NEXT: jle .LBB0_4
; CHECK-NEXT: # %bb.3: # %bb_dec
; CHECK-NEXT: decl %eax
; CHECK-NEXT: movl %eax, (%rdi)
; CHECK-NEXT: retq
%count = load i32, ptr %p, align 4
%cmp0 = icmp eq i32 %count, 1
br i1 %cmp0, label %bb_free, label %bb2
bb2:
%cmp1 = icmp sgt i32 %count, 1
br i1 %cmp1, label %bb_dec, label %end
bb_dec:
%dec = add nsw i32 %count, -1
store i32 %dec, ptr %p, align 4
br label %end
bb_free:
call void @free_object()
br label %end
end:
ret void
}
declare void @free_object()
|
