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-rw-r--r--llvm/lib/Analysis/BranchProbabilityInfo.cpp24
-rw-r--r--llvm/unittests/Analysis/BranchProbabilityInfoTest.cpp88
-rw-r--r--llvm/unittests/Analysis/CMakeLists.txt1
3 files changed, 101 insertions, 12 deletions
diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
index a91ac8d06fa..3eabb780398 100644
--- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
@@ -162,12 +162,12 @@ bool BranchProbabilityInfo::calcUnreachableHeuristics(const BasicBlock *BB) {
return true;
}
- BranchProbability UnreachableProb(UR_TAKEN_WEIGHT,
- (UR_TAKEN_WEIGHT + UR_NONTAKEN_WEIGHT) *
- UnreachableEdges.size());
- BranchProbability ReachableProb(UR_NONTAKEN_WEIGHT,
- (UR_TAKEN_WEIGHT + UR_NONTAKEN_WEIGHT) *
- ReachableEdges.size());
+ auto UnreachableProb = BranchProbability::getBranchProbability(
+ UR_TAKEN_WEIGHT, (UR_TAKEN_WEIGHT + UR_NONTAKEN_WEIGHT) *
+ uint64_t(UnreachableEdges.size()));
+ auto ReachableProb = BranchProbability::getBranchProbability(
+ UR_NONTAKEN_WEIGHT,
+ (UR_TAKEN_WEIGHT + UR_NONTAKEN_WEIGHT) * uint64_t(ReachableEdges.size()));
for (unsigned SuccIdx : UnreachableEdges)
setEdgeProbability(BB, SuccIdx, UnreachableProb);
@@ -300,12 +300,12 @@ bool BranchProbabilityInfo::calcColdCallHeuristics(const BasicBlock *BB) {
return true;
}
- BranchProbability ColdProb(CC_TAKEN_WEIGHT,
- (CC_TAKEN_WEIGHT + CC_NONTAKEN_WEIGHT) *
- ColdEdges.size());
- BranchProbability NormalProb(CC_NONTAKEN_WEIGHT,
- (CC_TAKEN_WEIGHT + CC_NONTAKEN_WEIGHT) *
- NormalEdges.size());
+ auto ColdProb = BranchProbability::getBranchProbability(
+ CC_TAKEN_WEIGHT,
+ (CC_TAKEN_WEIGHT + CC_NONTAKEN_WEIGHT) * uint64_t(ColdEdges.size()));
+ auto NormalProb = BranchProbability::getBranchProbability(
+ CC_NONTAKEN_WEIGHT,
+ (CC_TAKEN_WEIGHT + CC_NONTAKEN_WEIGHT) * uint64_t(NormalEdges.size()));
for (unsigned SuccIdx : ColdEdges)
setEdgeProbability(BB, SuccIdx, ColdProb);
diff --git a/llvm/unittests/Analysis/BranchProbabilityInfoTest.cpp b/llvm/unittests/Analysis/BranchProbabilityInfoTest.cpp
new file mode 100644
index 00000000000..cbf8b50c762
--- /dev/null
+++ b/llvm/unittests/Analysis/BranchProbabilityInfoTest.cpp
@@ -0,0 +1,88 @@
+//===- BranchProbabilityInfoTest.cpp - BranchProbabilityInfo unit tests ---===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+namespace {
+
+struct BranchProbabilityInfoTest : public testing::Test {
+ std::unique_ptr<BranchProbabilityInfo> BPI;
+ std::unique_ptr<DominatorTree> DT;
+ std::unique_ptr<LoopInfo> LI;
+ LLVMContext C;
+
+ BranchProbabilityInfo &buildBPI(Function &F) {
+ DT.reset(new DominatorTree(F));
+ LI.reset(new LoopInfo(*DT));
+ BPI.reset(new BranchProbabilityInfo(F, *LI));
+ return *BPI;
+ }
+
+ std::unique_ptr<Module> makeLLVMModule() {
+ const char *ModuleString = "define void @f() { exit: ret void }\n";
+ SMDiagnostic Err;
+ return parseAssemblyString(ModuleString, Err, C);
+ }
+};
+
+TEST_F(BranchProbabilityInfoTest, StressUnreachableHeuristic) {
+ auto M = makeLLVMModule();
+ Function *F = M->getFunction("f");
+
+ // define void @f() {
+ // entry:
+ // switch i32 undef, label %exit, [
+ // i32 0, label %preexit
+ // ... ;;< Add lots of cases to stress the heuristic.
+ // ]
+ // preexit:
+ // unreachable
+ // exit:
+ // ret void
+ // }
+
+ auto *ExitBB = &F->back();
+ auto *EntryBB = BasicBlock::Create(C, "entry", F, /*insertBefore=*/ExitBB);
+
+ auto *PreExitBB =
+ BasicBlock::Create(C, "preexit", F, /*insertBefore=*/ExitBB);
+ new UnreachableInst(C, PreExitBB);
+
+ unsigned NumCases = 4096;
+ auto *I32 = IntegerType::get(C, 32);
+ auto *Undef = UndefValue::get(I32);
+ auto *Switch = SwitchInst::Create(Undef, ExitBB, NumCases, EntryBB);
+ for (unsigned I = 0; I < NumCases; ++I)
+ Switch->addCase(ConstantInt::get(I32, I), PreExitBB);
+
+ BranchProbabilityInfo &BPI = buildBPI(*F);
+
+ // FIXME: This doesn't seem optimal. Since all of the cases handled by the
+ // switch have the *same* destination block ("preexit"), shouldn't it be the
+ // hot one? I'd expect the results to be reversed here...
+ EXPECT_FALSE(BPI.isEdgeHot(EntryBB, PreExitBB));
+ EXPECT_TRUE(BPI.isEdgeHot(EntryBB, ExitBB));
+}
+
+} // end anonymous namespace
+} // end namespace llvm
diff --git a/llvm/unittests/Analysis/CMakeLists.txt b/llvm/unittests/Analysis/CMakeLists.txt
index 347c3be5147..33fc5c78ce5 100644
--- a/llvm/unittests/Analysis/CMakeLists.txt
+++ b/llvm/unittests/Analysis/CMakeLists.txt
@@ -8,6 +8,7 @@ set(LLVM_LINK_COMPONENTS
add_llvm_unittest(AnalysisTests
AliasAnalysisTest.cpp
BlockFrequencyInfoTest.cpp
+ BranchProbabilityInfoTest.cpp
CallGraphTest.cpp
CFGTest.cpp
CGSCCPassManagerTest.cpp
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