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pass validator
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‎llvm/include/llvm/Transforms/Utils/ProfileVerify.h

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//===- ProfileVerify.h - Verify profile info for testing ----0-----*-C++-*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Inject profile information, as part of tests, to verify passes don't
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// accidentally drop it.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_UTILS_PROFILEVERIFY_H
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#define LLVM_TRANSFORMS_UTILS_PROFILEVERIFY_H
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#include "llvm/IR/Analysis.h"
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#include "llvm/IR/PassManager.h"
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namespace llvm {
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/// Inject MD_prof metadata where it's missing. Used for testing that passes
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/// don't accidentally drop this metadata.
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class ProfileInjectorPass : public PassInfoMixin<ProfileInjectorPass> {
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public:
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PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);
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};
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/// Checks that MD_prof is present on every instruction that supports it. Used
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/// in conjunction with the ProfileInjectorPass. MD_prof "unknown" is considered
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/// valid (i.e. !{!"unknown"})
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class ProfileVerifierPass : public PassInfoMixin<ProfileVerifierPass> {
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public:
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PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);
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};
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} // namespace llvm
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#endif

‎llvm/lib/Passes/PassBuilder.cpp

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#include "llvm/Transforms/Utils/MoveAutoInit.h"
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#include "llvm/Transforms/Utils/NameAnonGlobals.h"
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#include "llvm/Transforms/Utils/PredicateInfo.h"
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#include "llvm/Transforms/Utils/ProfileVerify.h"
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#include "llvm/Transforms/Utils/RelLookupTableConverter.h"
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#include "llvm/Transforms/Utils/StripGCRelocates.h"
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#include "llvm/Transforms/Utils/StripNonLineTableDebugInfo.h"

‎llvm/lib/Passes/PassRegistry.def

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@@ -517,6 +517,8 @@ FUNCTION_PASS("print<regions>", RegionInfoPrinterPass(errs()))
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FUNCTION_PASS("print<scalar-evolution>", ScalarEvolutionPrinterPass(errs()))
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FUNCTION_PASS("print<stack-safety-local>", StackSafetyPrinterPass(errs()))
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FUNCTION_PASS("print<uniformity>", UniformityInfoPrinterPass(errs()))
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FUNCTION_PASS("prof-inject", ProfileInjectorPass())
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FUNCTION_PASS("prof-verify", ProfileVerifierPass())
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FUNCTION_PASS("reassociate", ReassociatePass())
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FUNCTION_PASS("redundant-dbg-inst-elim", RedundantDbgInstEliminationPass())
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FUNCTION_PASS("reg2mem", RegToMemPass())

‎llvm/lib/Transforms/Utils/CMakeLists.txt

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@@ -67,6 +67,7 @@ add_llvm_component_library(LLVMTransformUtils
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MoveAutoInit.cpp
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NameAnonGlobals.cpp
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PredicateInfo.cpp
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ProfileVerify.cpp
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PromoteMemoryToRegister.cpp
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RelLookupTableConverter.cpp
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ScalarEvolutionExpander.cpp

‎llvm/lib/Transforms/Utils/ProfileVerify.cpp

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//===- ProfileVerify.cpp - Verify profile info for testing ----------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/ProfileVerify.h"
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#include "llvm/ADT/DynamicAPInt.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Analysis/BranchProbabilityInfo.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/IR/Analysis.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/ProfDataUtils.h"
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#include "llvm/Support/BranchProbability.h"
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using namespace llvm;
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namespace {
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class ProfileInjector {
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Function &F;
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FunctionAnalysisManager &FAM;
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public:
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static bool supportsBranchWeights(const Instruction &I) {
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return isa<BranchInst>(&I) ||
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isa<SwitchInst>(&I) ||
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isa<IndirectBrInst>(&I) || isa<SelectInst>(&I) ||
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isa<CallBrInst>(&I);
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}
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ProfileInjector(Function &F, FunctionAnalysisManager &FAM) : F(F), FAM(FAM) {}
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bool inject();
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};
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} // namespace
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bool ProfileInjector::inject() {
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auto &BPI = FAM.getResult<BranchProbabilityAnalysis>(F);
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for (auto &BB : F) {
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if (succ_size(&BB) <= 1)
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continue;
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auto *Term = BB.getTerminator();
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assert(Term);
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if (Term->getMetadata(LLVMContext::MD_prof) ||
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!supportsBranchWeights(*Term))
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continue;
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SmallVector<BranchProbability> Probs;
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Probs.reserve(Term->getNumSuccessors());
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for (auto I = 0U, E = Term->getNumSuccessors(); I < E; ++I)
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Probs.emplace_back(BPI.getEdgeProbability(&BB, Term->getSuccessor(I)));
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const auto *FirstZeroDenominator =
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find_if(Probs, [](const BranchProbability &P) {
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return P.getDenominator() == 0;
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});
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assert(FirstZeroDenominator == Probs.end());
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const auto *FirstNonzeroNumerator =
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find_if(Probs, [](const BranchProbability &P) {
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return P.getNumerator() != 0;
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});
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assert(FirstNonzeroNumerator != Probs.end());
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DynamicAPInt LCM(Probs[0].getDenominator());
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DynamicAPInt GCD(FirstNonzeroNumerator->getNumerator());
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for (const auto &Prob : drop_begin(Probs)) {
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if (!Prob.getNumerator())
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continue;
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LCM = llvm::lcm(LCM, DynamicAPInt(Prob.getDenominator()));
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GCD = llvm::lcm(GCD, DynamicAPInt(Prob.getNumerator()));
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}
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SmallVector<uint32_t> Weights;
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Weights.reserve(Term->getNumSuccessors());
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for (const auto &Prob : Probs) {
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auto W = Prob.getNumerator() * LCM / GCD;
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Weights.emplace_back(static_cast<int32_t>((int64_t)W));
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}
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setBranchWeights(*Term, Weights, false);
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}
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return true;
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}
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PreservedAnalyses ProfileInjectorPass::run(Function &F,
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FunctionAnalysisManager &FAM) {
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ProfileInjector PI(F, FAM);
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if (!PI.inject())
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return PreservedAnalyses::all();
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return PreservedAnalyses::none();
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}
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PreservedAnalyses ProfileVerifierPass::run(Function &F,
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FunctionAnalysisManager &FAM) {
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bool Changed = false;
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for (auto &BB : F)
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if (succ_size(&BB) >= 2)
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if (auto *Term = BB.getTerminator())
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if (ProfileInjector::supportsBranchWeights(*Term)) {
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if (!Term->getMetadata(LLVMContext::MD_prof)) {
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F.getContext().emitError("Profile verification failed");
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} else {
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Changed = true;
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}
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}
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return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();
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}

‎llvm/test/Transforms/PGOProfile/prof-verify-as-needed.ll

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; Test that prof-inject only injects missing metadata
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; RUN: opt -passes=prof-inject %s -S -o - | FileCheck %s
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define void @foo(i32 %i) {
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%c = icmp eq i32 %i, 0
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br i1 %c, label %yes, label %no, !prof !0
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yes:
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br i1 %c, label %yes2, label %no
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yes2:
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ret void
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no:
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ret void
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}
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!0 = !{!"branch_weights", i32 1, i32 2}
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; CHECK: br i1 %c, label %yes, label %no, !prof !0
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; CHECK: br i1 %c, label %yes2, label %no, !prof !1
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; CHECK: !0 = !{!"branch_weights", i32 1, i32 2}
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; CHECK: !1 = !{!"branch_weights", i32 429496729, i32 715827882}

‎llvm/test/Transforms/PGOProfile/prof-verify-existing.ll

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; Test that prof-verify does not modify existing metadata (incl. "unknown")
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; RUN: opt -passes=prof-inject %s -S -o - | FileCheck %s
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; RUN: opt -passes=prof-verify %s -S --disable-output
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define void @foo(i32 %i) {
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%c = icmp eq i32 %i, 0
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br i1 %c, label %yes, label %no, !prof !0
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yes:
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br i1 %c, label %yes2, label %no, !prof !1
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yes2:
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ret void
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no:
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ret void
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}
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!0 = !{!"branch_weights", i32 1, i32 2}
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!1 = !{!"unknown"}
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; CHECK: br i1 %c, label %yes, label %no, !prof !0
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; CHECK: !0 = !{!"branch_weights", i32 1, i32 2}
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; CHECK: !1 = !{!"unknown"}

‎llvm/test/Transforms/PGOProfile/prof-verify.ll

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; Test prof-inject and prof-verify
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; RUN: opt -passes=prof-inject %s -S -o - | FileCheck %s --check-prefix=INJECT
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; RUN: not opt -passes=prof-verify %s -S -o - 2>&1 | FileCheck %s --check-prefix=VERIFY
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; RUN: opt -passes=prof-inject,prof-verify %s --disable-output
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define void @foo(i32 %i) {
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%c = icmp eq i32 %i, 0
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br i1 %c, label %yes, label %no
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yes:
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ret void
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no:
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ret void
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}
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; INJECT: br i1 %c, label %yes, label %no, !prof !0
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; INJECT: !0 = !{!"branch_weights", i32 429496729, i32 715827882}
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; VERIFY: Profile verification failed

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