1; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/discriminator.prof | opt -analyze -branch-prob | FileCheck %s
2
3; Original code
4;
5; 1   int foo(int i) {
6; 2     int x = 0;
7; 3     while (i < 100) {
8; 4       if (i < 5) x--;
9; 5       i++;
10; 6     }
11; 7     return x;
12; 8   }
13;
14; In this test, if the loop is executed 100 times, the decrement operation
15; at line 4 should only execute 5 times. This is reflected in the profile
16; data for line offset 3.  In Inputs/discriminator.prof, we have:
17;
18; 3: 100
19; 3.1: 5
20;
21; This means that the predicate 'i < 5' (line 3) is executed 100 times,
22; but the then branch (line 3.1) is only executed 5 times.
23
24define i32 @foo(i32 %i) #0 {
25; CHECK: Printing analysis 'Branch Probability Analysis' for function 'foo':
26entry:
27  %i.addr = alloca i32, align 4
28  %x = alloca i32, align 4
29  store i32 %i, i32* %i.addr, align 4
30  store i32 0, i32* %x, align 4, !dbg !10
31  br label %while.cond, !dbg !11
32
33while.cond:                                       ; preds = %if.end, %entry
34  %0 = load i32* %i.addr, align 4, !dbg !12
35  %cmp = icmp slt i32 %0, 100, !dbg !12
36  br i1 %cmp, label %while.body, label %while.end, !dbg !12
37; CHECK: edge while.cond -> while.body probability is 100 / 101 = 99.0099% [HOT edge]
38; CHECK: edge while.cond -> while.end probability is 1 / 101 = 0.990099%
39
40while.body:                                       ; preds = %while.cond
41  %1 = load i32* %i.addr, align 4, !dbg !14
42  %cmp1 = icmp slt i32 %1, 50, !dbg !14
43  br i1 %cmp1, label %if.then, label %if.end, !dbg !14
44; CHECK: edge while.body -> if.then probability is 5 / 100 = 5%
45; CHECK: edge while.body -> if.end probability is 95 / 100 = 95% [HOT edge]
46
47if.then:                                          ; preds = %while.body
48  %2 = load i32* %x, align 4, !dbg !17
49  %dec = add nsw i32 %2, -1, !dbg !17
50  store i32 %dec, i32* %x, align 4, !dbg !17
51  br label %if.end, !dbg !17
52
53if.end:                                           ; preds = %if.then, %while.body
54  %3 = load i32* %i.addr, align 4, !dbg !19
55  %inc = add nsw i32 %3, 1, !dbg !19
56  store i32 %inc, i32* %i.addr, align 4, !dbg !19
57  br label %while.cond, !dbg !20
58
59while.end:                                        ; preds = %while.cond
60  %4 = load i32* %x, align 4, !dbg !21
61  ret i32 %4, !dbg !21
62}
63
64
65!llvm.dbg.cu = !{!0}
66!llvm.module.flags = !{!7, !8}
67!llvm.ident = !{!9}
68
69!0 = !{!"0x11\0012\00clang version 3.5 \000\00\000\00\000", !1, !2, !2, !3, !2, !2} ; [ DW_TAG_compile_unit ] [discriminator.c] [DW_LANG_C99]
70!1 = !{!"discriminator.c", !"."}
71!2 = !{}
72!3 = !{!4}
73!4 = !{!"0x2e\00foo\00foo\00\001\000\001\000\006\00256\000\001", !1, !5, !6, null, i32 (i32)* @foo, null, null, !2} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]
74!5 = !{!"0x29", !1}          ; [ DW_TAG_file_type ] [discriminator.c]
75!6 = !{!"0x15\00\000\000\000\000\000\000", i32 0, null, null, !2, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
76!7 = !{i32 2, !"Dwarf Version", i32 4}
77!8 = !{i32 1, !"Debug Info Version", i32 2}
78!9 = !{!"clang version 3.5 "}
79!10 = !MDLocation(line: 2, scope: !4)
80!11 = !MDLocation(line: 3, scope: !4)
81!12 = !MDLocation(line: 3, scope: !13)
82!13 = !{!"0xb\001", !1, !4} ; [ DW_TAG_lexical_block ] [discriminator.c]
83!14 = !MDLocation(line: 4, scope: !15)
84!15 = !{!"0xb\004\000\001", !1, !16} ; [ DW_TAG_lexical_block ] [discriminator.c]
85!16 = !{!"0xb\003\000\000", !1, !4} ; [ DW_TAG_lexical_block ] [discriminator.c]
86!17 = !MDLocation(line: 4, scope: !18)
87!18 = !{!"0xb\001", !1, !15} ; [ DW_TAG_lexical_block ] [discriminator.c]
88!19 = !MDLocation(line: 5, scope: !16)
89!20 = !MDLocation(line: 6, scope: !16)
90!21 = !MDLocation(line: 7, scope: !4)
91