1; RUN: llc %s -o - -mtriple=thumbv8m.base | FileCheck %s
2
3declare i32 @g(...)
4
5declare i32 @h0(i32, i32, i32, i32)
6define hidden i32 @f0() {
7  %1 = tail call i32 bitcast (i32 (...)* @g to i32 ()*)()
8  %2 = tail call i32 @h0(i32 %1, i32 1, i32 2, i32 3)
9  ret i32 %2
10; CHECK-LABEL: f0
11; CHECK:      ldr     [[POP:r[4567]]], [sp, #4]
12; CHECK-NEXT: mov     lr, [[POP]]
13; CHECK-NEXT: pop     {{.*}}[[POP]]
14; CHECK-NEXT: add     sp, #4
15; CHECK-NEXT: b       h0
16}
17
18declare i32 @h1(i32)
19define hidden i32 @f1() {
20  %1 = tail call i32 bitcast (i32 (...)* @g to i32 ()*)()
21  %2 = tail call i32 @h1(i32 %1)
22  ret i32 %2
23; CHECK-LABEL: f1
24; CHECK: pop     {r7}
25; CHECK: pop     {r1}
26; CHECK: mov     lr, r1
27; CHECK: b       h1
28}
29
30declare i32 @h2(i32, i32, i32, i32, i32)
31define hidden i32 @f2(i32, i32, i32, i32, i32) {
32  %6 = tail call i32 bitcast (i32 (...)* @g to i32 ()*)()
33  %7 = icmp eq i32 %6, 0
34  br i1 %7, label %10, label %8
35
36  %9 = tail call i32 @h2(i32 %6, i32 %1, i32 %2, i32 %3, i32 %4)
37  br label %10
38
39  %11 = phi i32 [ %9, %8 ], [ -1, %5 ]
40  ret i32 %11
41; CHECK-LABEL: f2
42; CHECK:      ldr     [[POP:r[4567]]], [sp, #12]
43; CHECK-NEXT: mov     lr, [[POP]]
44; CHECK-NEXT: pop     {{.*}}[[POP]]
45; CHECK-NEXT: add     sp, #4
46; CHECK-NEXT: b       h2
47}
48
49; Make sure that tail calls to function pointers that require r0-r3 for argument
50; passing do not break the compiler.
51@fnptr = global i32 (i32, i32, i32, i32)* null
52define i32 @test3() {
53; CHECK-LABEL: test3:
54; CHECK: blx {{r[0-9]+}}
55  %1 = load i32 (i32, i32, i32, i32)*, i32 (i32, i32, i32, i32)** @fnptr
56  %2 = tail call i32 %1(i32 1, i32 2, i32 3, i32 4)
57  ret i32 %2
58}
59
60@fnptr2 = global i32 (i32, i32, i64)* null
61define i32 @test4() {
62; CHECK-LABEL: test4:
63; CHECK: blx {{r[0-9]+}}
64  %1 = load i32 (i32, i32, i64)*, i32 (i32, i32, i64)** @fnptr2
65  %2 = tail call i32 %1(i32 1, i32 2, i64 3)
66  ret i32 %2
67}
68
69; Check that tail calls to function pointers where not all of r0-r3 are used for
70; parameter passing are tail-call optimized.
71; test5: params in r0, r1. r2 & r3 are free.
72@fnptr3 = global i32 (i32, i32)* null
73define i32 @test5() {
74; CHECK-LABEL: test5:
75; CHECK: ldr [[REG:r[0-9]+]]
76; CHECK: bx [[REG]]
77; CHECK-NOT: blx [[REG]]
78  %1 = load i32 (i32, i32)*, i32 (i32, i32)** @fnptr3
79  %2 = tail call i32 %1(i32 1, i32 2)
80  ret i32 %2
81}
82
83; test6: params in r0 and r2-r3. r1 is free.
84@fnptr4 = global i32 (i32, i64)* null
85define i32 @test6() {
86; CHECK-LABEL: test6:
87; CHECK: ldr [[REG:r[0-9]+]]
88; CHECK: bx [[REG]]
89; CHECK-NOT: blx [[REG]]
90  %1 = load i32 (i32, i64)*, i32 (i32, i64)** @fnptr4
91  %2 = tail call i32 %1(i32 1, i64 2)
92  ret i32 %2
93}
94
95; Check that tail calls to functions other than function pointers are
96; tail-call optimized.
97define i32 @test7() {
98; CHECK-LABEL: test7:
99; CHECK: b bar
100; CHECK-NOT: bl bar
101  %tail = tail call i32 @bar(i32 1, i32 2, i32 3, i32 4)
102  ret i32 %tail
103}
104
105declare i32 @bar(i32, i32, i32, i32)
106
107; Regression test for failure to load indirect branch target (class tcGPR) from
108; a stack slot.
109%struct.S = type { i32 }
110
111define void @test8(i32 (i32, i32, i32)* nocapture %fn, i32 %x) local_unnamed_addr {
112entry:
113  %call = tail call %struct.S* bitcast (%struct.S* (...)* @test8_u to %struct.S* ()*)()
114  %a = getelementptr inbounds %struct.S, %struct.S* %call, i32 0, i32 0
115  %0 = load i32, i32* %a, align 4
116  %call1 = tail call i32 @test8_h(i32 0)
117  %call2 = tail call i32 @test8_g(i32 %0, i32 %call1, i32 0)
118  store i32 %x, i32* %a, align 4
119  %call4 = tail call i32 %fn(i32 1, i32 2, i32 3)
120  ret void
121}
122
123declare %struct.S* @test8_u(...)
124
125declare i32 @test8_g(i32, i32, i32)
126
127declare i32 @test8_h(i32)
128; CHECK: str r0, [sp] @ 4-byte Spill
129; CHECK: ldr r3, [sp] @ 4-byte Reload
130; CHECK: bx r3
131