e3cf80c5c1
BlockFrequencyInfo calculates block frequencies as Scaled64 numbers but as a last step converts them to unsigned 64bit integers (`BlockFrequency`). This improves the factors picked for this conversion so that: * Avoid big numbers close to UINT64_MAX to avoid users overflowing/saturating when adding multiply frequencies together or when multiplying with integers. This leaves the topmost 10 bits unused to allow for some room. * Spread the difference between hottest/coldest block as much as possible to increase precision. * If the hot/cold spread cannot be represented loose precision at the lower end, but keep the frequencies at the upper end for hot blocks differentiable.
81 lines
4.1 KiB
LLVM
81 lines
4.1 KiB
LLVM
; RUN: opt < %s -passes='pseudo-probe-update' -S | FileCheck %s
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declare i32 @f1()
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declare i32 @f2()
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declare void @f3()
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define i32 @foo(i1 %cond, i1 %cond2) !dbg !4 !prof !10 {
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 1, i32 0, i64 -1)
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br i1 %cond, label %T1, label %Merge, !prof !11
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T1: ; preds = %0
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%v1 = call i32 @f1(), !prof !12
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%cond3 = icmp eq i32 %v1, 412
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 2, i32 0, i64 -1)
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;; The distribution factor -9223372036854775808 stands for 53.85%, whic is from 7/6+7.
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; CHECK: call void @llvm.pseudoprobe(i64 [[#GUID:]], i64 4, i32 0, i64 -9223372036854775808)
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 4, i32 0, i64 -1), !dbg !13
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;; Probe 7 has two copies, since they don't share the same inline context, they are not
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;; considered sharing samples, thus their distribution factors are not fixed up.
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; CHECK: call void @llvm.pseudoprobe(i64 [[#GUID]], i64 7, i32 0, i64 -1)
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 7, i32 0, i64 -1), !dbg !13
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;; Similar to Probe 7, one copy of Probe 8 doesn't have inline context.
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; CHECK: call void @llvm.pseudoprobe(i64 [[#GUID]], i64 8, i32 0, i64 -1)
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 8, i32 0, i64 -1), !dbg !13
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br i1 %cond3, label %T2, label %F2, !prof !11
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Merge: ; preds = %0
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%v2 = call i32 @f2(), !prof !12
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 3, i32 0, i64 -1)
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;; The distribution factor -9223372036854775808 stands for 46.25%, which is from 6/6+7.
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; CHECK: call void @llvm.pseudoprobe(i64 [[#GUID]], i64 4, i32 0, i64 -9223372036854775808)
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 4, i32 0, i64 8513881922462547968), !dbg !13
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; CHECK: call void @llvm.pseudoprobe(i64 [[#GUID]], i64 7, i32 0, i64 -1)
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 7, i32 0, i64 -1), !dbg !18
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; CHECK: call void @llvm.pseudoprobe(i64 [[#GUID]], i64 8, i32 0, i64 -1)
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 8, i32 0, i64 -1), !dbg !19
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br i1 %cond2, label %T2, label %F2, !prof !11
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T2: ; preds = %Merge, %T1
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%B1 = phi i32 [ %v1, %T1 ], [ %v2, %Merge ]
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call void @f3(), !prof !12
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 5, i32 0, i64 -1)
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ret i32 %B1
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F2: ; preds = %Merge, %T1
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%B2 = phi i32 [ %v1, %T1 ], [ %v2, %Merge ]
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call void @llvm.pseudoprobe(i64 6699318081062747564, i64 6, i32 0, i64 -1)
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ret i32 %B2
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}
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; Function Attrs: inaccessiblememonly nounwind willreturn
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declare void @llvm.pseudoprobe(i64, i64, i32, i64) #0
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attributes #0 = { inaccessiblememonly nounwind willreturn }
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!llvm.module.flags = !{!0, !1}
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!llvm.pseudo_probe_desc = !{!2, !3}
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!0 = !{i32 7, !"Dwarf Version", i32 4}
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!1 = !{i32 2, !"Debug Info Version", i32 3}
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!2 = !{i64 6699318081062747564, i64 281479271677951, !"foo", null}
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!3 = !{i64 6468398850841090686, i64 138828622701, !"zen", null}
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!4 = distinct !DISubprogram(name: "foo", scope: !5, file: !5, line: 9, type: !6, scopeLine: 9, spFlags: DISPFlagDefinition, unit: !9)
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!5 = !DIFile(filename: "test.cpp", directory: "test")
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!6 = !DISubroutineType(types: !7)
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!7 = !{!8, !8}
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!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!9 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !5, isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
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!10 = !{!"function_entry_count", i64 14}
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!11 = !{!"branch_weights", i32 8, i32 7}
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!12 = !{!"branch_weights", i32 7}
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!13 = !DILocation(line: 39, column: 9, scope: !14, inlinedAt: !16)
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!14 = distinct !DILexicalBlock(scope: !15, file: !5, line: 39, column: 7)
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!15 = distinct !DISubprogram(name: "zen", scope: !5, file: !5, line: 37, type: !6, scopeLine: 38, spFlags: DISPFlagDefinition, unit: !9)
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!16 = distinct !DILocation(line: 10, column: 11, scope: !17)
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!17 = !DILexicalBlockFile(scope: !4, file: !5, discriminator: 186646551)
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!18 = !DILocation(line: 53, column: 3, scope: !15, inlinedAt: !19)
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!19 = !DILocation(line: 12, column: 3, scope: !4)
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