xref: /llvm-project/llvm/test/Transforms/Inline/noinline-recursive-fn.ll (revision 151602c7a9935558ca671b35359989b261045db0)
1; The inliner should never inline recursive functions into other functions.
2; This effectively is just peeling off the first iteration of a loop, and the
3; inliner heuristics are not set up for this.
4
5; RUN: opt -passes=inline -S < %s | FileCheck %s
6; RUN: opt -passes='cgscc(inline)' -S < %s | FileCheck %s
7
8target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
9target triple = "x86_64-apple-darwin10.3"
10
11@g = common global i32 0                          ; <ptr> [#uses=1]
12
13define internal void @foo(i32 %x) nounwind ssp {
14entry:
15  %0 = icmp slt i32 %x, 0                         ; <i1> [#uses=1]
16  br i1 %0, label %return, label %bb
17
18bb:                                               ; preds = %entry
19  %1 = sub nsw i32 %x, 1                          ; <i32> [#uses=1]
20  call void @foo(i32 %1) nounwind ssp
21  store volatile i32 1, ptr @g, align 4
22  ret void
23
24return:                                           ; preds = %entry
25  ret void
26}
27
28
29;; CHECK-LABEL: @bonk(
30;; CHECK: call void @foo(i32 42)
31define void @bonk() nounwind ssp {
32entry:
33  call void @foo(i32 42) nounwind ssp
34  ret void
35}
36
37
38
39;; Here is an indirect case that should not be infinitely inlined.
40
41define internal void @f1(i32 %x, ptr %Foo, ptr %Bar) nounwind ssp {
42entry:
43  %0 = sub nsw i32 %x, 1
44  call void %Bar(i32 %0, ptr %Foo, ptr %Bar) nounwind
45  store volatile i32 42, ptr @g, align 4
46  ret void
47}
48
49define internal void @f2(i32 %x, ptr %Foo, ptr %Bar) nounwind ssp {
50entry:
51  %0 = icmp slt i32 %x, 0                         ; <i1> [#uses=1]
52  br i1 %0, label %return, label %bb
53
54bb:                                               ; preds = %entry
55  call void %Foo(i32 %x, ptr %Foo, ptr %Bar) nounwind
56  store volatile i32 13, ptr @g, align 4
57  ret void
58
59return:                                           ; preds = %entry
60  ret void
61}
62
63
64; CHECK-LABEL: @top_level(
65; CHECK: call void @f2(i32 122
66; Here we inline one instance of the cycle, but we don't want to completely
67; unroll it.
68define void @top_level() nounwind ssp {
69entry:
70  call void @f2(i32 123, ptr @f1, ptr @f2) nounwind ssp
71  ret void
72}
73
74
75; Check that a recursive function, when called with a constant that makes the
76; recursive path dead code can actually be inlined.
77define i32 @fib(i32 %i) {
78entry:
79  %is.zero = icmp eq i32 %i, 0
80  br i1 %is.zero, label %zero.then, label %zero.else
81
82zero.then:
83  ret i32 0
84
85zero.else:
86  %is.one = icmp eq i32 %i, 1
87  br i1 %is.one, label %one.then, label %one.else
88
89one.then:
90  ret i32 1
91
92one.else:
93  %i1 = sub i32 %i, 1
94  %f1 = call i32 @fib(i32 %i1)
95  %i2 = sub i32 %i, 2
96  %f2 = call i32 @fib(i32 %i2)
97  %f = add i32 %f1, %f2
98  ret i32 %f
99}
100
101define i32 @fib_caller() {
102; CHECK-LABEL: @fib_caller(
103; CHECK-NOT: call
104; CHECK: ret
105  %f1 = call i32 @fib(i32 0)
106  %f2 = call i32 @fib(i32 1)
107  %result = add i32 %f1, %f2
108  ret i32 %result
109}
110