1 ; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/discriminator.prof | opt -analyze -branch-prob | FileCheck %s 2 ; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/discriminator.prof | opt -analyze -branch-prob | FileCheck %s 3 4 ; Original code 5 ; 6 ; 1 int foo(int i) { 7 ; 2 int x = 0; 8 ; 3 while (i < 100) { 9 ; 4 if (i < 5) x--; 10 ; 5 i++; 11 ; 6 } 12 ; 7 return x; 13 ; 8 } 14 ; 15 ; In this test, if the loop is executed 100 times, the decrement operation 16 ; at line 4 should only execute 5 times. This is reflected in the profile 17 ; data for line offset 3. In Inputs/discriminator.prof, we have: 18 ; 19 ; 3: 100 20 ; 3.1: 5 21 ; 22 ; This means that the predicate 'i < 5' (line 3) is executed 100 times, 23 ; but the then branch (line 3.1) is only executed 5 times. 24 25 define i32 @foo(i32 %i) #0 !dbg !4 { 26 ; CHECK: Printing analysis 'Branch Probability Analysis' for function 'foo': 27 entry: 28 %i.addr = alloca i32, align 4 29 %x = alloca i32, align 4 30 store i32 %i, i32* %i.addr, align 4 31 store i32 0, i32* %x, align 4, !dbg !10 32 br label %while.cond, !dbg !11 33 34 while.cond: ; preds = %if.end, %entry 35 %0 = load i32, i32* %i.addr, align 4, !dbg !12 36 %cmp = icmp slt i32 %0, 100, !dbg !12 37 br i1 %cmp, label %while.body, label %while.end, !dbg !12 38 ; CHECK: edge while.cond -> while.body probability is 0x7ebb907a / 0x80000000 = 99.01% [HOT edge] 39 ; CHECK: edge while.cond -> while.end probability is 0x01446f86 / 0x80000000 = 0.99% 40 41 while.body: ; preds = %while.cond 42 %1 = load i32, i32* %i.addr, align 4, !dbg !14 43 %cmp1 = icmp slt i32 %1, 50, !dbg !14 44 br i1 %cmp1, label %if.then, label %if.end, !dbg !14 45 ; CHECK: edge while.body -> if.then probability is 0x06666666 / 0x80000000 = 5.00% 46 ; CHECK: edge while.body -> if.end probability is 0x7999999a / 0x80000000 = 95.00% [HOT edge] 47 48 if.then: ; preds = %while.body 49 %2 = load i32, i32* %x, align 4, !dbg !17 50 %dec = add nsw i32 %2, -1, !dbg !17 51 store i32 %dec, i32* %x, align 4, !dbg !17 52 br label %if.end, !dbg !17 53 54 if.end: ; preds = %if.then, %while.body 55 %3 = load i32, i32* %i.addr, align 4, !dbg !19 56 %inc = add nsw i32 %3, 1, !dbg !19 57 store i32 %inc, i32* %i.addr, align 4, !dbg !19 58 br label %while.cond, !dbg !20 59 60 while.end: ; preds = %while.cond 61 %4 = load i32, i32* %x, align 4, !dbg !21 62 ret i32 %4, !dbg !21 63 } 64 65 66 !llvm.dbg.cu = !{!0} 67 !llvm.module.flags = !{!7, !8} 68 !llvm.ident = !{!9} 69 70 !0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.5 ", isOptimized: false, emissionKind: NoDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2) 71 !1 = !DIFile(filename: "discriminator.c", directory: ".") 72 !2 = !{} 73 !4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, 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
