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InstrProf: Mark BiasLI as invariant. #95588

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Merged
merged 2 commits into from
Jul 20, 2024
Merged

InstrProf: Mark BiasLI as invariant. #95588

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InstrProf: Mark BiasLI as invariant.
chapuni Jun 14, 2024
361de6c
Merge branch 'main' into mcdc/bias_invariant
chapuni Jun 19, 2024
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3 changes: 3 additions & 0 deletions llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -932,6 +932,9 @@ Value *InstrLowerer::getCounterAddress(InstrProfCntrInstBase *I) {
IRBuilder<> EntryBuilder(&Fn->getEntryBlock().front());
auto *Bias = getOrCreateBiasVar(getInstrProfCounterBiasVarName());
BiasLI = EntryBuilder.CreateLoad(Int64Ty, Bias, "profc_bias");
// Bias doesn't change after startup.
BiasLI->setMetadata(LLVMContext::MD_invariant_load,
MDNode::get(M.getContext(), std::nullopt));
}
auto *Add = Builder.CreateAdd(Builder.CreatePtrToInt(Addr, Int64Ty), BiasLI);
return Builder.CreateIntToPtr(Add, Addr->getType());
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26 changes: 25 additions & 1 deletion llvm/test/Instrumentation/InstrProfiling/runtime-counter-relocation.ll
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@@ -1,9 +1,13 @@
; RUN: opt < %s -S -passes=instrprof | FileCheck %s
; RUN: opt < %s -S -passes=instrprof -runtime-counter-relocation | FileCheck -check-prefixes=RELOC %s
; RUN: opt < %s -S -passes=instrprof,inline,gvn -runtime-counter-relocation | FileCheck -check-prefixes=RELOC,RELOCOPT %s
; RUN: opt < %s -S -passes=instrprof -runtime-counter-relocation -instrprof-atomic-counter-update-all | FileCheck -check-prefixes=ATOMIC %s
; RUN: opt < %s -S -passes=instrprof,inline,gvn -runtime-counter-relocation -instrprof-atomic-counter-update-all | FileCheck -check-prefixes=ATOMIC,ATOMICOPT %s

target triple = "x86_64-unknown-linux-gnu"

@__profn_foo = private constant [3 x i8] c"foo"
@__profn_bar = private constant [3 x i8] c"bar"
; RELOC: $__llvm_profile_counter_bias = comdat any
; RELOC: @__llvm_profile_counter_bias = linkonce_odr hidden global i64 0, comdat

Expand All @@ -12,14 +16,34 @@ target triple = "x86_64-unknown-linux-gnu"
; CHECK-NEXT: %[[PGOCOUNTINC:.+]] = add i64 %[[PGOCOUNT]], 1
; CHECK-NEXT: store i64 %[[PGOCOUNTINC]], ptr @__profc_foo
; RELOC-LABEL: define void @foo
; RELOC-NEXT: %[[BIAS:.+]] = load i64, ptr @__llvm_profile_counter_bias
; RELOC-NEXT: %[[BIAS:.+]] = load i64, ptr @__llvm_profile_counter_bias, align 8, !invariant.load !0
; RELOC-NEXT: %[[PROFC_BIAS:.+]] = add i64 ptrtoint (ptr @__profc_foo to i64), %[[BIAS]]
; RELOC-NEXT: %[[PROFC_ADDR:.+]] = inttoptr i64 %[[PROFC_BIAS]] to ptr
; RELOC-NEXT: %[[PGOCOUNT:.+]] = load i64, ptr %[[PROFC_ADDR]]
; RELOC-NEXT: %[[PGOCOUNTINC:.+]] = add i64 %[[PGOCOUNT]], 1
; RELOC-NEXT: store i64 %[[PGOCOUNTINC]], ptr %[[PROFC_ADDR]]
; RELOCOPT-NEXT: %[[PROFC_BIAS1:.+]] = add i64 ptrtoint (ptr @__profc_bar to i64), %[[BIAS]]
; RELOCOPT-NEXT: %[[PROFC_ADDR1:.+]] = inttoptr i64 %[[PROFC_BIAS1]] to ptr
; RELOCOPT-NEXT: %[[PGOCOUNT1:.+]] = load i64, ptr %[[PROFC_ADDR1]]
; RELOCOPT-NEXT: %[[PGOCOUNTINC1:.+]] = add i64 %[[PGOCOUNT1]], 1
; RELOCOPT-NEXT: store i64 %[[PGOCOUNTINC1]], ptr %[[PROFC_ADDR1]]
; ATOMIC-LABEL: define void @foo
; ATOMIC-NEXT: %[[BIAS:.+]] = load i64, ptr @__llvm_profile_counter_bias, align 8, !invariant.load !0
; ATOMIC-NEXT: %[[PROFC_BIAS:.+]] = add i64 ptrtoint (ptr @__profc_foo to i64), %[[BIAS]]
; ATOMIC-NEXT: %[[PROFC_ADDR:.+]] = inttoptr i64 %[[PROFC_BIAS]] to ptr
; ATOMIC-NEXT: %[[PGOCOUNTINC:.+]] = atomicrmw add ptr %[[PROFC_ADDR]], i64 1 monotonic
; ATOMICOPT-NEXT: %[[PROFC_BIAS1:.+]] = add i64 ptrtoint (ptr @__profc_bar to i64), %[[BIAS]]
; ATOMICOPT-NEXT: %[[PROFC_ADDR1:.+]] = inttoptr i64 %[[PROFC_BIAS1]] to ptr
; ATOMICOPT-NEXT: %[[PGOCOUNTINC1:.+]] = atomicrmw add ptr %[[PROFC_ADDR1]], i64 1 monotonic

define void @bar() {
call void @llvm.instrprof.increment(ptr @__profn_bar, i64 0, i32 1, i32 0)
ret void
}

define void @foo() {
call void @llvm.instrprof.increment(ptr @__profn_foo, i64 0, i32 1, i32 0)
call void @bar()
ret void
}

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