| ; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/discriminator.prof | opt -analyze -branch-prob | FileCheck %s |
| ; RUN: opt < %s -passes=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 !dbg !4 { |
| ; 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, 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 0x7d83ba68 / 0x80000000 = 98.06% [HOT edge] |
| ; CHECK: edge while.cond -> while.end probability is 0x027c4598 / 0x80000000 = 1.94% |
| |
| while.body: ; preds = %while.cond |
| %1 = load i32, 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 0x07878788 / 0x80000000 = 5.88% |
| ; CHECK: edge while.body -> if.end probability is 0x78787878 / 0x80000000 = 94.12% [HOT edge] |
| |
| if.then: ; preds = %while.body |
| %2 = load i32, 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, 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, i32* %x, align 4, !dbg !21 |
| ret i32 %4, !dbg !21 |
| } |
| |
| |
| !llvm.dbg.cu = !{!0} |
| !llvm.module.flags = !{!7, !8} |
| !llvm.ident = !{!9} |
| |
| !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) |
| !1 = !DIFile(filename: "discriminator.c", directory: ".") |
| !2 = !{} |
| !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, retainedNodes: !2) |
| !5 = !DIFile(filename: "discriminator.c", directory: ".") |
| !6 = !DISubroutineType(types: !2) |
| !7 = !{i32 2, !"Dwarf Version", i32 4} |
| !8 = !{i32 1, !"Debug Info Version", i32 3} |
| !9 = !{!"clang version 3.5 "} |
| !10 = !DILocation(line: 2, scope: !4) |
| !11 = !DILocation(line: 3, scope: !4) |
| !12 = !DILocation(line: 3, scope: !13) |
| !13 = !DILexicalBlockFile(discriminator: 2, file: !1, scope: !4) |
| !14 = !DILocation(line: 4, scope: !15) |
| !15 = distinct !DILexicalBlock(line: 4, column: 0, file: !1, scope: !16) |
| !16 = distinct !DILexicalBlock(line: 3, column: 0, file: !1, scope: !4) |
| !17 = !DILocation(line: 4, scope: !18) |
| !18 = !DILexicalBlockFile(discriminator: 2, file: !1, scope: !15) |
| !19 = !DILocation(line: 5, scope: !16) |
| !20 = !DILocation(line: 6, scope: !16) |
| !21 = !DILocation(line: 7, scope: !4) |