llvm-6502/test/Transforms/SampleProfile/discriminator.ll

; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/discriminator.prof | opt -analyze -branch-prob | FileCheck %s

; Original code
;
; 1   int foo(int i) {
; 2     int x = 0;
; 3     while (i < 100) {
; 4       if (i < 5) x--;
; 5       i++;
; 6     }
; 7     return x;
; 8   }
;
; In this test, if the loop is executed 100 times, the decrement operation
; at line 4 should only execute 5 times. This is reflected in the profile
; data for line offset 3.  In Inputs/discriminator.prof, we have:
;
; 3: 100
; 3.1: 5
;
; This means that the predicate 'i < 5' (line 3) is executed 100 times,
; but the then branch (line 3.1) is only executed 5 times.

define i32 @foo(i32 %i) #0 {
; CHECK: Printing analysis 'Branch Probability Analysis' for function 'foo':
entry:
  %i.addr = alloca i32, align 4
  %x = alloca i32, align 4
  store i32 %i, i32* %i.addr, align 4
  store i32 0, i32* %x, align 4, !dbg !10
  br label %while.cond, !dbg !11

while.cond:                                       ; preds = %if.end, %entry
  %0 = load i32* %i.addr, align 4, !dbg !12
  %cmp = icmp slt i32 %0, 100, !dbg !12
  br i1 %cmp, label %while.body, label %while.end, !dbg !12
; CHECK: edge while.cond -> while.body probability is 100 / 101 = 99.0099% [HOT edge]
; CHECK: edge while.cond -> while.end probability is 1 / 101 = 0.990099%

while.body:                                       ; preds = %while.cond
  %1 = load i32* %i.addr, align 4, !dbg !14
  %cmp1 = icmp slt i32 %1, 50, !dbg !14
  br i1 %cmp1, label %if.then, label %if.end, !dbg !14
; CHECK: edge while.body -> if.then probability is 5 / 100 = 5%
; CHECK: edge while.body -> if.end probability is 95 / 100 = 95% [HOT edge]

if.then:                                          ; preds = %while.body
  %2 = load i32* %x, align 4, !dbg !17
  %dec = add nsw i32 %2, -1, !dbg !17
  store i32 %dec, i32* %x, align 4, !dbg !17
  br label %if.end, !dbg !17

if.end:                                           ; preds = %if.then, %while.body
  %3 = load i32* %i.addr, align 4, !dbg !19
  %inc = add nsw i32 %3, 1, !dbg !19
  store i32 %inc, i32* %i.addr, align 4, !dbg !19
  br label %while.cond, !dbg !20

while.end:                                        ; preds = %while.cond
  %4 = load i32* %x, align 4, !dbg !21
  ret i32 %4, !dbg !21
}


!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!7, !8}
!llvm.ident = !{!9}

!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [discriminator.c] [DW_LANG_C99]
!1 = metadata !{metadata !"discriminator.c", metadata !"."}
!2 = metadata !{}
!3 = metadata !{metadata !4}
!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"foo", metadata !"foo", metadata !"", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 (i32)* @foo, null, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]
!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [discriminator.c]
!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !2, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!7 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!8 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
!9 = metadata !{metadata !"clang version 3.5 "}
!10 = metadata !{i32 2, i32 0, metadata !4, null}
!11 = metadata !{i32 3, i32 0, metadata !4, null}
!12 = metadata !{i32 3, i32 0, metadata !13, null}
!13 = metadata !{i32 786443, metadata !1, metadata !4, i32 3, i32 0, i32 1, i32 2} ; [ DW_TAG_lexical_block ] [discriminator.c]
!14 = metadata !{i32 4, i32 0, metadata !15, null}
!15 = metadata !{i32 786443, metadata !1, metadata !16, i32 4, i32 0, i32 0, i32 1} ; [ DW_TAG_lexical_block ] [discriminator.c]
!16 = metadata !{i32 786443, metadata !1, metadata !4, i32 3, i32 0, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [discriminator.c]
!17 = metadata !{i32 4, i32 0, metadata !18, null}
!18 = metadata !{i32 786443, metadata !1, metadata !15, i32 4, i32 0, i32 1, i32 3} ; [ DW_TAG_lexical_block ] [discriminator.c]
!19 = metadata !{i32 5, i32 0, metadata !16, null}
!20 = metadata !{i32 6, i32 0, metadata !16, null}
!21 = metadata !{i32 7, i32 0, metadata !4, null}