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 24 define i32 @foo(i32 %i) #0 !dbg !4 { 25 ; CHECK: Printing analysis 'Branch Probability Analysis' for function 'foo': 26 entry: 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 33 while.cond: ; preds = %if.end, %entry 34 %0 = load i32, 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 0x7ebb907a / 0x80000000 = 99.01% [HOT edge] 38 ; CHECK: edge while.cond -> while.end probability is 0x01446f86 / 0x80000000 = 0.99% 39 40 while.body: ; preds = %while.cond 41 %1 = load i32, 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 0x06666666 / 0x80000000 = 5.00% 45 ; CHECK: edge while.body -> if.end probability is 0x7999999a / 0x80000000 = 95.00% [HOT edge] 46 47 if.then: ; preds = %while.body 48 %2 = load i32, 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 53 if.end: ; preds = %if.then, %while.body 54 %3 = load i32, 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 59 while.end: ; preds = %while.cond 60 %4 = load i32, 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 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.5 ", isOptimized: false, emissionKind: 0, file: !1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2) 70 !1 = !DIFile(filename: "discriminator.c", directory: ".") 71 !2 = !{} 72 !3 = !{!4} 73 !4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 1, file: !1, scope: !5, type: !6, variables: !2) 74 !5 = !DIFile(filename: "discriminator.c", directory: ".") 75 !6 = !DISubroutineType(types: !2) 76 !7 = !{i32 2, !"Dwarf Version", i32 4} 77 !8 = !{i32 1, !"Debug Info Version", i32 3} 78 !9 = !{!"clang version 3.5 "} 79 !10 = !DILocation(line: 2, scope: !4) 80 !11 = !DILocation(line: 3, scope: !4) 81 !12 = !DILocation(line: 3, scope: !13) 82 !13 = !DILexicalBlockFile(discriminator: 1, file: !1, scope: !4) 83 !14 = !DILocation(line: 4, scope: !15) 84 !15 = distinct !DILexicalBlock(line: 4, column: 0, file: !1, scope: !16) 85 !16 = distinct !DILexicalBlock(line: 3, column: 0, file: !1, scope: !4) 86 !17 = !DILocation(line: 4, scope: !18) 87 !18 = !DILexicalBlockFile(discriminator: 1, file: !1, scope: !15) 88 !19 = !DILocation(line: 5, scope: !16) 89 !20 = !DILocation(line: 6, scope: !16) 90 !21 = !DILocation(line: 7, scope: !4) 91
