24bf6ff4e0
Based on internal testing at Google we found that setting the profile summary cutoff threshold to 999950 yields the best results in terms of itlb and icache metrics (as observed on Intel CPUs). *default* = Split out code if no profile count available for block *size-%* = The fraction of bytes split out of .text and .text.hot *itlb* = Misses per kilo instructions (MPKI) for itlb *icache* = Misses per kilo instructions (MPKI) for L1 icache Search1 | cutoff | size-% | itlb | icache | |---------|---------|-----------|---------| | default | 42.5861 | 0.0822151 | 2.46363 | | 999999 | 44.9350 | 0.0767194 | 2.44416 | | 999950 | 50.0660 | 0.075744 | 2.4091 | | 999500 | 56.9158 | 0.082564 | 2.4188 | | 995000 | 63.8625 | 0.0814927 | 2.42832 | | 990000 | 71.7314 | 0.106906 | 2.57785 | Search2 | cutoff | size-% | itlb | icache | |---------|--------|----------|---------| | default | 2.8845 | 0.626712 | 4.73245 | | 999999 | 3.3291 | 0.602309 | 4.70045 | | 999950 | 3.8577 | 0.587842 | 4.71632 | | 999500 | 4.4170 | 0.63577 | 4.68351 | | 995000 | 5.1020 | 0.657969 | 4.82272 | | 990000 | 5.7153 | 0.719122 | 5.39496 | Differential Revision: https://reviews.llvm.org/D89085
219 lines
5.9 KiB
LLVM
219 lines
5.9 KiB
LLVM
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -split-machine-functions | FileCheck %s -check-prefix=MFS-DEFAULTS
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; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -split-machine-functions -mfs-psi-cutoff=0 -mfs-count-threshold=2000 | FileCheck %s --dump-input=always -check-prefix=MFS-OPTS1
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; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -split-machine-functions -mfs-psi-cutoff=950000 | FileCheck %s -check-prefix=MFS-OPTS2
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define void @foo1(i1 zeroext %0) nounwind !prof !14 !section_prefix !15 {
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;; Check that cold block is moved to .text.split.
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; MFS-DEFAULTS-LABEL: foo1
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; MFS-DEFAULTS: .section .text.split.foo1
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; MFS-DEFAULTS-NEXT: foo1.cold:
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; MFS-DEFAULTS-NOT: callq bar
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; MFS-DEFAULTS-NEXT: callq baz
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br i1 %0, label %2, label %4, !prof !17
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2: ; preds = %1
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%3 = call i32 @bar()
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br label %6
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4: ; preds = %1
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%5 = call i32 @baz()
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br label %6
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6: ; preds = %4, %2
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%7 = tail call i32 @qux()
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ret void
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}
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define void @foo2(i1 zeroext %0) nounwind !prof !23 !section_prefix !16 {
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;; Check that function marked unlikely is not split.
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; MFS-DEFAULTS-LABEL: foo2
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; MFS-DEFAULTS-NOT: foo2.cold:
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br i1 %0, label %2, label %4, !prof !17
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2: ; preds = %1
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%3 = call i32 @bar()
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br label %6
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4: ; preds = %1
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%5 = call i32 @baz()
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br label %6
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6: ; preds = %4, %2
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%7 = tail call i32 @qux()
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ret void
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}
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define void @foo3(i1 zeroext %0) nounwind !section_prefix !15 {
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;; Check that function without profile data is not split.
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; MFS-DEFAULTS-LABEL: foo3
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; MFS-DEFAULTS-NOT: foo3.cold:
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br i1 %0, label %2, label %4
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2: ; preds = %1
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%3 = call i32 @bar()
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br label %6
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4: ; preds = %1
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%5 = call i32 @baz()
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br label %6
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6: ; preds = %4, %2
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%7 = tail call i32 @qux()
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ret void
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}
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define void @foo4(i1 zeroext %0, i1 zeroext %1) nounwind !prof !20 {
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;; Check that count threshold works.
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; MFS-OPTS1-LABEL: foo4
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; MFS-OPTS1: .section .text.split.foo4
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; MFS-OPTS1-NEXT: foo4.cold:
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; MFS-OPTS1-NOT: callq bar
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; MFS-OPTS1-NOT: callq baz
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; MFS-OPTS1-NEXT: callq bam
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br i1 %0, label %3, label %7, !prof !18
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3:
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%4 = call i32 @bar()
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br label %7
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5:
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%6 = call i32 @baz()
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br label %7
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7:
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br i1 %1, label %8, label %10, !prof !19
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8:
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%9 = call i32 @bam()
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br label %12
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10:
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%11 = call i32 @baz()
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br label %12
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12:
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%13 = tail call i32 @qux()
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ret void
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}
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define void @foo5(i1 zeroext %0, i1 zeroext %1) nounwind !prof !20 {
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;; Check that profile summary info cutoff works.
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; MFS-OPTS2-LABEL: foo5
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; MFS-OPTS2: .section .text.split.foo5
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; MFS-OPTS2-NEXT: foo5.cold:
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; MFS-OPTS2-NOT: callq bar
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; MFS-OPTS2-NOT: callq baz
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; MFS-OPTS2-NEXT: callq bam
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br i1 %0, label %3, label %7, !prof !21
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3:
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%4 = call i32 @bar()
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br label %7
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5:
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%6 = call i32 @baz()
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br label %7
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7:
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br i1 %1, label %8, label %10, !prof !22
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8:
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%9 = call i32 @bam()
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br label %12
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10:
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%11 = call i32 @baz()
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br label %12
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12:
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%13 = call i32 @qux()
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ret void
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}
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define void @foo6(i1 zeroext %0) nounwind section "nosplit" !prof !14 {
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;; Check that function with section attribute is not split.
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; MFS-DEFAULTS-LABEL: foo6
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; MFS-DEFAULTS-NOT: foo6.cold:
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br i1 %0, label %2, label %4, !prof !17
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2: ; preds = %1
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%3 = call i32 @bar()
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br label %6
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4: ; preds = %1
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%5 = call i32 @baz()
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br label %6
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6: ; preds = %4, %2
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%7 = tail call i32 @qux()
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ret void
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}
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define i32 @foo7(i1 zeroext %0) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) !prof !14 {
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;; Check that cold ehpads are not split out.
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; MFS-DEFAULTS-LABEL: foo7
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; MFS-DEFAULTS: .section .text.split.foo7,"ax",@progbits
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; MFS-DEFAULTS-NEXT: foo7.cold:
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; MFS-DEFAULTS-NOT: callq _Unwind_Resume
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; MFS-DEFAULTS: callq baz
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entry:
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invoke void @_Z1fv()
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to label %try.cont unwind label %lpad
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lpad:
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%1 = landingpad { i8*, i32 }
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cleanup
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catch i8* bitcast (i8** @_ZTIi to i8*)
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resume { i8*, i32 } %1
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try.cont:
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br i1 %0, label %2, label %4, !prof !17
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2: ; preds = try.cont
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%3 = call i32 @bar()
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br label %6
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4: ; preds = %1
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%5 = call i32 @baz()
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br label %6
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6: ; preds = %4, %2
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%7 = tail call i32 @qux()
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ret i32 %7
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}
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declare i32 @bar()
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declare i32 @baz()
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declare i32 @bam()
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declare i32 @qux()
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declare void @_Z1fv()
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declare i32 @__gxx_personality_v0(...)
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@_ZTIi = external constant i8*
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!llvm.module.flags = !{!0}
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!0 = !{i32 1, !"ProfileSummary", !1}
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!1 = !{!2, !3, !4, !5, !6, !7, !8, !9}
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!2 = !{!"ProfileFormat", !"InstrProf"}
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!3 = !{!"TotalCount", i64 10000}
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!4 = !{!"MaxCount", i64 10}
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!5 = !{!"MaxInternalCount", i64 1}
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!6 = !{!"MaxFunctionCount", i64 1000}
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!7 = !{!"NumCounts", i64 3}
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!8 = !{!"NumFunctions", i64 5}
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!9 = !{!"DetailedSummary", !10}
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!10 = !{!11, !12, !13}
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!11 = !{i32 10000, i64 100, i32 1}
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!12 = !{i32 999900, i64 100, i32 1}
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!13 = !{i32 999999, i64 1, i32 2}
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!14 = !{!"function_entry_count", i64 7000}
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!15 = !{!"function_section_prefix", !".hot"}
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!16 = !{!"function_section_prefix", !".unlikely"}
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!17 = !{!"branch_weights", i32 7000, i32 0}
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!18 = !{!"branch_weights", i32 3000, i32 4000}
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!19 = !{!"branch_weights", i32 1000, i32 6000}
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!20 = !{!"function_entry_count", i64 10000}
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!21 = !{!"branch_weights", i32 6000, i32 4000}
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!22 = !{!"branch_weights", i32 80, i32 9920}
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!23 = !{!"function_entry_count", i64 7}
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