1; RUN: opt -codegenprepare -S < %s | FileCheck %s
2
3target triple = "x86_64-unknown-unknown"
4
5; Nothing to sink here, but this gets converted to a branch to
6; avoid stalling an out-of-order CPU on a predictable branch.
7
8define i32 @no_sink(double %a, double* %b, i32 %x, i32 %y)  {
9entry:
10  %load = load double, double* %b, align 8
11  %cmp = fcmp olt double %load, %a
12  %sel = select i1 %cmp, i32 %x, i32 %y
13  ret i32 %sel
14
15; CHECK-LABEL: @no_sink(
16; CHECK:    %load = load double, double* %b, align 8
17; CHECK:    %cmp = fcmp olt double %load, %a
18; CHECK:    br i1 %cmp, label %select.end, label %select.false
19; CHECK:  select.false:
20; CHECK:    br label %select.end
21; CHECK:  select.end:
22; CHECK:    %sel = phi i32 [ %x, %entry ], [ %y, %select.false ]
23; CHECK:    ret i32 %sel
24}
25
26
27; An 'fdiv' is expensive, so sink it rather than speculatively execute it.
28
29define float @fdiv_true_sink(float %a, float %b) {
30entry:
31  %div = fdiv float %a, %b
32  %cmp = fcmp ogt float %a, 1.0
33  %sel = select i1 %cmp, float %div, float 2.0
34  ret float %sel
35
36; CHECK-LABEL: @fdiv_true_sink(
37; CHECK:    %cmp = fcmp ogt float %a, 1.0
38; CHECK:    br i1 %cmp, label %select.true.sink, label %select.end
39; CHECK:  select.true.sink:
40; CHECK:    %div = fdiv float %a, %b
41; CHECK:    br label %select.end
42; CHECK:  select.end:
43; CHECK:    %sel = phi float [ %div, %select.true.sink ], [ 2.000000e+00, %entry ]
44; CHECK:    ret float %sel
45}
46
47define float @fdiv_false_sink(float %a, float %b) {
48entry:
49  %div = fdiv float %a, %b
50  %cmp = fcmp ogt float %a, 3.0
51  %sel = select i1 %cmp, float 4.0, float %div
52  ret float %sel
53
54; CHECK-LABEL: @fdiv_false_sink(
55; CHECK:    %cmp = fcmp ogt float %a, 3.0
56; CHECK:    br i1 %cmp, label %select.end, label %select.false.sink
57; CHECK:  select.false.sink:
58; CHECK:    %div = fdiv float %a, %b
59; CHECK:    br label %select.end
60; CHECK:  select.end:
61; CHECK:    %sel = phi float [ 4.000000e+00, %entry ], [ %div, %select.false.sink ]
62; CHECK:    ret float %sel
63}
64
65define float @fdiv_both_sink(float %a, float %b) {
66entry:
67  %div1 = fdiv float %a, %b
68  %div2 = fdiv float %b, %a
69  %cmp = fcmp ogt float %a, 5.0
70  %sel = select i1 %cmp, float %div1, float %div2
71  ret float %sel
72
73; CHECK-LABEL: @fdiv_both_sink(
74; CHECK:    %cmp = fcmp ogt float %a, 5.0
75; CHECK:    br i1 %cmp, label %select.true.sink, label %select.false.sink
76; CHECK:  select.true.sink:
77; CHECK:    %div1 = fdiv float %a, %b
78; CHECK:    br label %select.end
79; CHECK:  select.false.sink:
80; CHECK:    %div2 = fdiv float %b, %a
81; CHECK:    br label %select.end
82; CHECK:  select.end:
83; CHECK:    %sel = phi float [ %div1, %select.true.sink ], [ %div2, %select.false.sink ]
84; CHECK:    ret float %sel
85}
86
87; An 'fadd' is not too expensive, so it's ok to speculate.
88
89define float @fadd_no_sink(float %a, float %b) {
90  %add = fadd float %a, %b
91  %cmp = fcmp ogt float 6.0, %a
92  %sel = select i1 %cmp, float %add, float 7.0
93  ret float %sel
94
95; CHECK-LABEL: @fadd_no_sink(
96; CHECK:  %sel = select i1 %cmp, float %add, float 7.0
97}
98
99; Possible enhancement: sinkability is only calculated with the direct
100; operand of the select, so we don't try to sink this. The fdiv cost is not
101; taken into account.
102
103define float @fdiv_no_sink(float %a, float %b) {
104entry:
105  %div = fdiv float %a, %b
106  %add = fadd float %div, %b
107  %cmp = fcmp ogt float %a, 1.0
108  %sel = select i1 %cmp, float %add, float 8.0
109  ret float %sel
110
111; CHECK-LABEL: @fdiv_no_sink(
112; CHECK:  %sel = select i1 %cmp, float %add, float 8.0
113}
114
115; Do not transform the CFG if the select operands may have side effects.
116
117declare i64* @bar(i32, i32, i32)
118declare i64* @baz(i32, i32, i32)
119
120define i64* @calls_no_sink(i32 %in) {
121  %call1 = call i64* @bar(i32 1, i32 2, i32 3)
122  %call2 = call i64* @baz(i32 1, i32 2, i32 3)
123  %tobool = icmp ne i32 %in, 0
124  %sel = select i1 %tobool, i64* %call1, i64* %call2
125  ret i64* %sel
126
127; CHECK-LABEL: @calls_no_sink(
128; CHECK:  %sel = select i1 %tobool, i64* %call1, i64* %call2
129}
130
131define i32 @sdiv_no_sink(i32 %a, i32 %b) {
132  %div1 = sdiv i32 %a, %b
133  %div2 = sdiv i32 %b, %a
134  %cmp = icmp sgt i32 %a, 5
135  %sel = select i1 %cmp, i32 %div1, i32 %div2
136  ret i32 %sel
137
138; CHECK-LABEL: @sdiv_no_sink(
139; CHECK:  %sel = select i1 %cmp, i32 %div1, i32 %div2
140}
141
142