Successfully identified regression in *llvm* in CI configuration
tcwg_bmk_llvm_tk1/llvm-release-arm-spec2k6-Os. So far, this commit has
regressed CI configurations:
- tcwg_bmk_llvm_tk1/llvm-release-arm-spec2k6-Os
Culprit:
<cut>
commit 3a2b05f9fe74fcf9560632cf2695058d47d8683b
Author: Evgeniy Brevnov <ybrev...@azul.com>
Date: Fri Jul 24 18:57:10 2020 +0700
[BPI][NFC] Consolidate code to deal with SCCs under a dedicated data
structure.
In order to facilitate review of D79485 here is a small NFC change which
restructures code around handling of SCCs in BPI.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D84514
</cut>
Results regressed to (for first_bad == 3a2b05f9fe74fcf9560632cf2695058d47d8683b)
# reset_artifacts:
-10
# build_abe binutils:
-9
# build_abe stage1 -- --set gcc_override_configure=--with-mode=thumb --set
gcc_override_configure=--disable-libsanitizer:
-8
# build_abe linux:
-7
# build_abe glibc:
-6
# build_abe stage2 -- --set gcc_override_configure=--with-mode=thumb --set
gcc_override_configure=--disable-libsanitizer:
-5
# build_llvm true:
-3
# true:
0
# benchmark -Os_mthumb --
artifacts/build-3a2b05f9fe74fcf9560632cf2695058d47d8683b/results_id:
1
# 401.bzip2,bzip2_base.default regressed by 104
from (for last_good == 7294ca3f6ecacd05a197bbf0637e10afcb99b6d6)
# reset_artifacts:
-10
# build_abe binutils:
-9
# build_abe stage1 -- --set gcc_override_configure=--with-mode=thumb --set
gcc_override_configure=--disable-libsanitizer:
-8
# build_abe linux:
-7
# build_abe glibc:
-6
# build_abe stage2 -- --set gcc_override_configure=--with-mode=thumb --set
gcc_override_configure=--disable-libsanitizer:
-5
# build_llvm true:
-3
# true:
0
# benchmark -Os_mthumb --
artifacts/build-7294ca3f6ecacd05a197bbf0637e10afcb99b6d6/results_id:
1
Artifacts of last_good build:
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/artifact/artifacts/build-7294ca3f6ecacd05a197bbf0637e10afcb99b6d6/
Results ID of last_good:
tk1_32/tcwg_bmk_llvm_tk1/bisect-llvm-release-arm-spec2k6-Os/699
Artifacts of first_bad build:
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/artifact/artifacts/build-3a2b05f9fe74fcf9560632cf2695058d47d8683b/
Results ID of first_bad:
tk1_32/tcwg_bmk_llvm_tk1/bisect-llvm-release-arm-spec2k6-Os/688
Build top page/logs:
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/
Configuration details:
Reproduce builds:
<cut>
mkdir investigate-llvm-3a2b05f9fe74fcf9560632cf2695058d47d8683b
cd investigate-llvm-3a2b05f9fe74fcf9560632cf2695058d47d8683b
git clone https://git.linaro.org/toolchain/jenkins-scripts
mkdir -p artifacts/manifests
curl -o artifacts/manifests/build-baseline.sh
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/artifact/artifacts/manifests/build-baseline.sh
--fail
curl -o artifacts/manifests/build-parameters.sh
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/artifact/artifacts/manifests/build-parameters.sh
--fail
curl -o artifacts/test.sh
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/artifact/artifacts/test.sh
--fail
chmod +x artifacts/test.sh
# Reproduce the baseline build (build all pre-requisites)
./jenkins-scripts/tcwg_bmk-build.sh @@ artifacts/manifests/build-baseline.sh
cd llvm
# Reproduce first_bad build
git checkout --detach 3a2b05f9fe74fcf9560632cf2695058d47d8683b
../artifacts/test.sh
# Reproduce last_good build
git checkout --detach 7294ca3f6ecacd05a197bbf0637e10afcb99b6d6
../artifacts/test.sh
cd ..
</cut>
History of pending regressions and results:
https://git.linaro.org/toolchain/ci/base-artifacts.git/log/?h=linaro-local/ci/tcwg_bmk_llvm_tk1/llvm-release-arm-spec2k6-Os
Artifacts:
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/artifact/artifacts/
Build log:
https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-release-arm-spec2k6-Os/15/consoleText
Full commit (up to 1000 lines):
<cut>
commit 3a2b05f9fe74fcf9560632cf2695058d47d8683b
Author: Evgeniy Brevnov <ybrev...@azul.com>
Date: Fri Jul 24 18:57:10 2020 +0700
[BPI][NFC] Consolidate code to deal with SCCs under a dedicated data
structure.
In order to facilitate review of D79485 here is a small NFC change which
restructures code around handling of SCCs in BPI.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D84514
---
llvm/include/llvm/Analysis/BranchProbabilityInfo.h | 71 ++++++++-
llvm/lib/Analysis/BranchProbabilityInfo.cpp | 164 +++++++++++++--------
2 files changed, 169 insertions(+), 66 deletions(-)
diff --git a/llvm/include/llvm/Analysis/BranchProbabilityInfo.h
b/llvm/include/llvm/Analysis/BranchProbabilityInfo.h
index 3e72afba36c3..7feb5b625938 100644
--- a/llvm/include/llvm/Analysis/BranchProbabilityInfo.h
+++ b/llvm/include/llvm/Analysis/BranchProbabilityInfo.h
@@ -151,13 +151,66 @@ public:
/// Forget analysis results for the given basic block.
void eraseBlock(const BasicBlock *BB);
- // Use to track SCCs for handling irreducible loops.
- using SccMap = DenseMap<const BasicBlock *, int>;
- using SccHeaderMap = DenseMap<const BasicBlock *, bool>;
- using SccHeaderMaps = std::vector<SccHeaderMap>;
- struct SccInfo {
+ class SccInfo {
+ // Enum of types to classify basic blocks in SCC. Basic block belonging to
+ // SCC is 'Inner' until it is either 'Header' or 'Exiting'. Note that a
+ // basic block can be 'Header' and 'Exiting' at the same time.
+ enum SccBlockType {
+ Inner = 0x0,
+ Header = 0x1,
+ Exiting = 0x2,
+ };
+ // Map of basic blocks to SCC IDs they belong to. If basic block doesn't
+ // belong to any SCC it is not in the map.
+ using SccMap = DenseMap<const BasicBlock *, int>;
+ // Each basic block in SCC is attributed with one or several types from
+ // SccBlockType. Map value has uint32_t type (instead of SccBlockType)
+ // since basic block may be for example "Header" and "Exiting" at the same
+ // time and we need to be able to keep more than one value from
+ // SccBlockType.
+ using SccBlockTypeMap = DenseMap<const BasicBlock *, uint32_t>;
+ // Vector containing classification of basic blocks for all SCCs where
i'th
+ // vector element corresponds to SCC with ID equal to i.
+ using SccBlockTypeMaps = std::vector<SccBlockTypeMap>;
+
SccMap SccNums;
- SccHeaderMaps SccHeaders;
+ SccBlockTypeMaps SccBlocks;
+
+ public:
+ explicit SccInfo(const Function &F);
+
+ /// If \p BB belongs to some SCC then ID of that SCC is returned, otherwise
+ /// -1 is returned. If \p BB belongs to more than one SCC at the same time
+ /// result is undefined.
+ int getSCCNum(const BasicBlock *BB) const;
+ /// Returns true if \p BB is a 'header' block in SCC with \p SccNum ID,
+ /// false otherwise.
+ bool isSCCHeader(const BasicBlock *BB, int SccNum) const {
+ return getSccBlockType(BB, SccNum) & Header;
+ }
+ /// Returns true if \p BB is an 'exiting' block in SCC with \p SccNum ID,
+ /// false otherwise.
+ bool isSCCExitingBlock(const BasicBlock *BB, int SccNum) const {
+ return getSccBlockType(BB, SccNum) & Exiting;
+ }
+ /// Fills in \p Enters vector with all such blocks that don't belong to
+ /// SCC with \p SccNum ID but there is an edge to a block belonging to the
+ /// SCC.
+ void getSccEnterBlocks(int SccNum,
+ SmallVectorImpl<BasicBlock *> &Enters) const;
+ /// Fills in \p Exits vector with all such blocks that don't belong to
+ /// SCC with \p SccNum ID but there is an edge from a block belonging to
the
+ /// SCC.
+ void getSccExitBlocks(int SccNum,
+ SmallVectorImpl<BasicBlock *> &Exits) const;
+
+ private:
+ /// Returns \p BB's type according to classification given by SccBlockType
+ /// enum. Please note that \p BB must belong to SSC with \p SccNum ID.
+ uint32_t getSccBlockType(const BasicBlock *BB, int SccNum) const;
+ /// Calculates \p BB's type and stores it in internal data structures for
+ /// future use. Please note that \p BB must belong to SSC with \p SccNum
ID.
+ void calculateSccBlockType(const BasicBlock *BB, int SccNum);
};
private:
@@ -196,6 +249,9 @@ private:
/// Track the last function we run over for printing.
const Function *LastF = nullptr;
+ /// Keeps information about all SCCs in a function.
+ std::unique_ptr<const SccInfo> SccI;
+
/// Track the set of blocks directly succeeded by a returning block.
SmallPtrSet<const BasicBlock *, 16> PostDominatedByUnreachable;
@@ -210,8 +266,7 @@ private:
bool calcMetadataWeights(const BasicBlock *BB);
bool calcColdCallHeuristics(const BasicBlock *BB);
bool calcPointerHeuristics(const BasicBlock *BB);
- bool calcLoopBranchHeuristics(const BasicBlock *BB, const LoopInfo &LI,
- SccInfo &SccI);
+ bool calcLoopBranchHeuristics(const BasicBlock *BB, const LoopInfo &LI);
bool calcZeroHeuristics(const BasicBlock *BB, const TargetLibraryInfo *TLI);
bool calcFloatingPointHeuristics(const BasicBlock *BB);
bool calcInvokeHeuristics(const BasicBlock *BB);
diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
index a396b5ad21c6..195fc69d9601 100644
--- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
@@ -148,6 +148,105 @@ static const uint32_t IH_TAKEN_WEIGHT = 1024 * 1024 - 1;
/// instruction. This is essentially never taken.
static const uint32_t IH_NONTAKEN_WEIGHT = 1;
+BranchProbabilityInfo::SccInfo::SccInfo(const Function &F) {
+ // Record SCC numbers of blocks in the CFG to identify irreducible loops.
+ // FIXME: We could only calculate this if the CFG is known to be irreducible
+ // (perhaps cache this info in LoopInfo if we can easily calculate it
there?).
+ int SccNum = 0;
+ for (scc_iterator<const Function *> It = scc_begin(&F); !It.isAtEnd();
+ ++It, ++SccNum) {
+ // Ignore single-block SCCs since they either aren't loops or LoopInfo will
+ // catch them.
+ const std::vector<const BasicBlock *> &Scc = *It;
+ if (Scc.size() == 1)
+ continue;
+
+ LLVM_DEBUG(dbgs() << "BPI: SCC " << SccNum << ":");
+ for (const auto *BB : Scc) {
+ LLVM_DEBUG(dbgs() << " " << BB->getName());
+ SccNums[BB] = SccNum;
+ calculateSccBlockType(BB, SccNum);
+ }
+ LLVM_DEBUG(dbgs() << "\n");
+ }
+}
+
+int BranchProbabilityInfo::SccInfo::getSCCNum(const BasicBlock *BB) const {
+ auto SccIt = SccNums.find(BB);
+ if (SccIt == SccNums.end())
+ return -1;
+ return SccIt->second;
+}
+
+void BranchProbabilityInfo::SccInfo::getSccEnterBlocks(
+ int SccNum, SmallVectorImpl<BasicBlock *> &Enters) const {
+
+ for (auto MapIt : SccBlocks[SccNum]) {
+ const auto *BB = MapIt.first;
+ if (isSCCHeader(BB, SccNum))
+ for (const auto *Pred : predecessors(BB))
+ if (getSCCNum(Pred) != SccNum)
+ Enters.push_back(const_cast<BasicBlock *>(BB));
+ }
+}
+
+void BranchProbabilityInfo::SccInfo::getSccExitBlocks(
+ int SccNum, SmallVectorImpl<BasicBlock *> &Exits) const {
+ for (auto MapIt : SccBlocks[SccNum]) {
+ const auto *BB = MapIt.first;
+ if (isSCCExitingBlock(BB, SccNum))
+ for (const auto *Succ : successors(BB))
+ if (getSCCNum(Succ) != SccNum)
+ Exits.push_back(const_cast<BasicBlock *>(BB));
+ }
+}
+
+uint32_t BranchProbabilityInfo::SccInfo::getSccBlockType(const BasicBlock *BB,
+ int SccNum) const {
+ assert(getSCCNum(BB) == SccNum);
+
+ assert(SccBlocks.size() > static_cast<unsigned>(SccNum) && "Unknown SCC");
+ const auto &SccBlockTypes = SccBlocks[SccNum];
+
+ auto It = SccBlockTypes.find(BB);
+ if (It != SccBlockTypes.end()) {
+ return It->second;
+ }
+ return Inner;
+}
+
+void BranchProbabilityInfo::SccInfo::calculateSccBlockType(const BasicBlock
*BB,
+ int SccNum) {
+ assert(getSCCNum(BB) == SccNum);
+ uint32_t BlockType = Inner;
+
+ if (llvm::any_of(make_range(pred_begin(BB), pred_end(BB)),
+ [&](const BasicBlock *Pred) {
+ // Consider any block that is an entry point to the SCC as
+ // a header.
+ return getSCCNum(Pred) != SccNum;
+ }))
+ BlockType |= Header;
+
+ if (llvm::any_of(
+ make_range(succ_begin(BB), succ_end(BB)),
+ [&](const BasicBlock *Succ) { return getSCCNum(Succ) != SccNum; }))
+ BlockType |= Exiting;
+
+ // Lazily compute the set of headers for a given SCC and cache the results
+ // in the SccHeaderMap.
+ if (SccBlocks.size() <= static_cast<unsigned>(SccNum))
+ SccBlocks.resize(SccNum + 1);
+ auto &SccBlockTypes = SccBlocks[SccNum];
+
+ if (BlockType != Inner) {
+ bool IsInserted;
+ std::tie(std::ignore, IsInserted) =
+ SccBlockTypes.insert(std::make_pair(BB, BlockType));
+ assert(IsInserted && "Duplicated block in SCC");
+ }
+}
+
static void UpdatePDTWorklist(const BasicBlock *BB, PostDominatorTree *PDT,
SmallVectorImpl<const BasicBlock *> &WorkList,
SmallPtrSetImpl<const BasicBlock *> &TargetSet) {
@@ -511,38 +610,6 @@ bool BranchProbabilityInfo::calcPointerHeuristics(const
BasicBlock *BB) {
return true;
}
-static int getSCCNum(const BasicBlock *BB,
- const BranchProbabilityInfo::SccInfo &SccI) {
- auto SccIt = SccI.SccNums.find(BB);
- if (SccIt == SccI.SccNums.end())
- return -1;
- return SccIt->second;
-}
-
-// Consider any block that is an entry point to the SCC as a header.
-static bool isSCCHeader(const BasicBlock *BB, int SccNum,
- BranchProbabilityInfo::SccInfo &SccI) {
- assert(getSCCNum(BB, SccI) == SccNum);
-
- // Lazily compute the set of headers for a given SCC and cache the results
- // in the SccHeaderMap.
- if (SccI.SccHeaders.size() <= static_cast<unsigned>(SccNum))
- SccI.SccHeaders.resize(SccNum + 1);
- auto &HeaderMap = SccI.SccHeaders[SccNum];
- bool Inserted;
- BranchProbabilityInfo::SccHeaderMap::iterator HeaderMapIt;
- std::tie(HeaderMapIt, Inserted) = HeaderMap.insert(std::make_pair(BB,
false));
- if (Inserted) {
- bool IsHeader = llvm::any_of(make_range(pred_begin(BB), pred_end(BB)),
- [&](const BasicBlock *Pred) {
- return getSCCNum(Pred, SccI) != SccNum;
- });
- HeaderMapIt->second = IsHeader;
- return IsHeader;
- } else
- return HeaderMapIt->second;
-}
-
// Compute the unlikely successors to the block BB in the loop L, specifically
// those that are unlikely because this is a loop, and add them to the
// UnlikelyBlocks set.
@@ -653,12 +720,11 @@ computeUnlikelySuccessors(const BasicBlock *BB, Loop *L,
// Calculate Edge Weights using "Loop Branch Heuristics". Predict backedges
// as taken, exiting edges as not-taken.
bool BranchProbabilityInfo::calcLoopBranchHeuristics(const BasicBlock *BB,
- const LoopInfo &LI,
- SccInfo &SccI) {
+ const LoopInfo &LI) {
int SccNum;
Loop *L = LI.getLoopFor(BB);
if (!L) {
- SccNum = getSCCNum(BB, SccI);
+ SccNum = SccI->getSCCNum(BB);
if (SccNum < 0)
return false;
}
@@ -685,9 +751,9 @@ bool BranchProbabilityInfo::calcLoopBranchHeuristics(const
BasicBlock *BB,
else
InEdges.push_back(I.getSuccessorIndex());
} else {
- if (getSCCNum(*I, SccI) != SccNum)
+ if (SccI->getSCCNum(*I) != SccNum)
ExitingEdges.push_back(I.getSuccessorIndex());
- else if (isSCCHeader(*I, SccNum, SccI))
+ else if (SccI->isSCCHeader(*I, SccNum))
BackEdges.push_back(I.getSuccessorIndex());
else
InEdges.push_back(I.getSuccessorIndex());
@@ -1072,26 +1138,7 @@ void BranchProbabilityInfo::calculate(const Function &F,
const LoopInfo &LI,
assert(PostDominatedByUnreachable.empty());
assert(PostDominatedByColdCall.empty());
- // Record SCC numbers of blocks in the CFG to identify irreducible loops.
- // FIXME: We could only calculate this if the CFG is known to be irreducible
- // (perhaps cache this info in LoopInfo if we can easily calculate it
there?).
- int SccNum = 0;
- SccInfo SccI;
- for (scc_iterator<const Function *> It = scc_begin(&F); !It.isAtEnd();
- ++It, ++SccNum) {
- // Ignore single-block SCCs since they either aren't loops or LoopInfo will
- // catch them.
- const std::vector<const BasicBlock *> &Scc = *It;
- if (Scc.size() == 1)
- continue;
-
- LLVM_DEBUG(dbgs() << "BPI: SCC " << SccNum << ":");
- for (auto *BB : Scc) {
- LLVM_DEBUG(dbgs() << " " << BB->getName());
- SccI.SccNums[BB] = SccNum;
- }
- LLVM_DEBUG(dbgs() << "\n");
- }
+ SccI = std::make_unique<SccInfo>(F);
std::unique_ptr<PostDominatorTree> PDTPtr;
@@ -1119,7 +1166,7 @@ void BranchProbabilityInfo::calculate(const Function &F,
const LoopInfo &LI,
continue;
if (calcColdCallHeuristics(BB))
continue;
- if (calcLoopBranchHeuristics(BB, LI, SccI))
+ if (calcLoopBranchHeuristics(BB, LI))
continue;
if (calcPointerHeuristics(BB))
continue;
@@ -1131,6 +1178,7 @@ void BranchProbabilityInfo::calculate(const Function &F,
const LoopInfo &LI,
PostDominatedByUnreachable.clear();
PostDominatedByColdCall.clear();
+ SccI.release();
if (PrintBranchProb &&
(PrintBranchProbFuncName.empty() ||
</cut>
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