[llvm] 3478551 - [GVN] introduce GVNOptions to control GVN pass behavior
Fedor Sergeev via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 16 09:30:14 PST 2020
Author: Fedor Sergeev
Date: 2020-01-16T20:21:08+03:00
New Revision: 3478551bf3d24ab20a52f1eddb5b4c9bd5c8bf77
URL: https://github.com/llvm/llvm-project/commit/3478551bf3d24ab20a52f1eddb5b4c9bd5c8bf77
DIFF: https://github.com/llvm/llvm-project/commit/3478551bf3d24ab20a52f1eddb5b4c9bd5c8bf77.diff
LOG: [GVN] introduce GVNOptions to control GVN pass behavior
There are a few global (cl::opt) controls that enable optional
behavior in GVN. Introduce GVNOptions that provide corresponding
per-pass instance controls.
That will allow to use GVN multiple times in pipeline each time
with different settings.
Reviewers: asbirlea, rnk, reames, skatkov, fhahn
Reviewed By: fhahn
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72732
Added:
Modified:
llvm/include/llvm/Transforms/Scalar/GVN.h
llvm/lib/Transforms/Scalar/GVN.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Transforms/Scalar/GVN.h b/llvm/include/llvm/Transforms/Scalar/GVN.h
index 5a3d30de16a3..84dd708a62d8 100644
--- a/llvm/include/llvm/Transforms/Scalar/GVN.h
+++ b/llvm/include/llvm/Transforms/Scalar/GVN.h
@@ -61,14 +61,51 @@ class GVNLegacyPass;
} // end namespace gvn
+/// A set of parameters to control various transforms performed by GVN pass.
+// Each of the optional boolean parameters can be set to:
+/// true - enabling the transformation.
+/// false - disabling the transformation.
+/// None - relying on a global default.
+/// Intended use is to create a default object, modify parameters with
+/// additional setters and then pass it to GVN.
+struct GVNOptions {
+ Optional<bool> AllowPRE = None;
+ Optional<bool> AllowLoadPRE = None;
+ Optional<bool> AllowMemDep = None;
+
+ GVNOptions() = default;
+
+ /// Enables or disables PRE in GVN.
+ GVNOptions &setPRE(bool PRE) {
+ AllowPRE = PRE;
+ return *this;
+ }
+
+ /// Enables or disables PRE of loads in GVN.
+ GVNOptions &setLoadPRE(bool LoadPRE) {
+ AllowLoadPRE = LoadPRE;
+ return *this;
+ }
+
+ /// Enables or disables use of MemDepAnalysis.
+ GVNOptions &setMemDep(bool MemDep) {
+ AllowMemDep = MemDep;
+ return *this;
+ }
+};
+
/// The core GVN pass object.
///
/// FIXME: We should have a good summary of the GVN algorithm implemented by
/// this particular pass here.
class GVN : public PassInfoMixin<GVN> {
+ GVNOptions Options;
+
public:
struct Expression;
+ GVN(GVNOptions Options = {}) : Options(Options) {}
+
/// Run the pass over the function.
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
@@ -83,6 +120,10 @@ class GVN : public PassInfoMixin<GVN> {
AliasAnalysis *getAliasAnalysis() const { return VN.getAliasAnalysis(); }
MemoryDependenceResults &getMemDep() const { return *MD; }
+ bool isPREEnabled() const;
+ bool isLoadPREEnabled() const;
+ bool isMemDepEnabled() const;
+
/// This class holds the mapping between values and value numbers. It is used
/// as an efficient mechanism to determine the expression-wise equivalence of
/// two values.
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index 1e6aab14e7b4..dbe26bbed1f2 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -97,10 +97,9 @@ STATISTIC(NumGVNSimpl, "Number of instructions simplified");
STATISTIC(NumGVNEqProp, "Number of equalities propagated");
STATISTIC(NumPRELoad, "Number of loads PRE'd");
-static cl::opt<bool> EnablePRE("enable-pre",
- cl::init(true), cl::Hidden);
-static cl::opt<bool> EnableLoadPRE("enable-load-pre", cl::init(true));
-static cl::opt<bool> EnableMemDep("enable-gvn-memdep", cl::init(true));
+static cl::opt<bool> GVNEnablePRE("enable-pre", cl::init(true), cl::Hidden);
+static cl::opt<bool> GVNEnableLoadPRE("enable-load-pre", cl::init(true));
+static cl::opt<bool> GVNEnableMemDep("enable-gvn-memdep", cl::init(true));
// Maximum allowed recursion depth.
static cl::opt<uint32_t>
@@ -610,6 +609,17 @@ void GVN::ValueTable::verifyRemoved(const Value *V) const {
// GVN Pass
//===----------------------------------------------------------------------===//
+bool GVN::isPREEnabled() const {
+ return Options.AllowPRE.getValueOr(GVNEnablePRE);
+}
+
+bool GVN::isLoadPREEnabled() const {
+ return Options.AllowLoadPRE.getValueOr(GVNEnableLoadPRE);
+}
+bool GVN::isMemDepEnabled() const {
+ return Options.AllowMemDep.getValueOr(GVNEnableMemDep);
+}
+
PreservedAnalyses GVN::run(Function &F, FunctionAnalysisManager &AM) {
// FIXME: The order of evaluation of these 'getResult' calls is very
// significant! Re-ordering these variables will cause GVN when run alone to
@@ -619,10 +629,11 @@ PreservedAnalyses GVN::run(Function &F, FunctionAnalysisManager &AM) {
auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
auto &AA = AM.getResult<AAManager>(F);
- auto &MemDep = AM.getResult<MemoryDependenceAnalysis>(F);
+ auto *MemDep =
+ isMemDepEnabled() ? &AM.getResult<MemoryDependenceAnalysis>(F) : nullptr;
auto *LI = AM.getCachedResult<LoopAnalysis>(F);
auto &ORE = AM.getResult<OptimizationRemarkEmitterAnalysis>(F);
- bool Changed = runImpl(F, AC, DT, TLI, AA, &MemDep, LI, &ORE);
+ bool Changed = runImpl(F, AC, DT, TLI, AA, MemDep, LI, &ORE);
if (!Changed)
return PreservedAnalyses::all();
PreservedAnalyses PA;
@@ -1383,7 +1394,7 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
}
// Step 4: Eliminate partial redundancy.
- if (!EnablePRE || !EnableLoadPRE)
+ if (!isPREEnabled() || !isLoadPREEnabled())
return false;
return PerformLoadPRE(LI, ValuesPerBlock, UnavailableBlocks);
@@ -2148,7 +2159,7 @@ bool GVN::runImpl(Function &F, AssumptionCache &RunAC, DominatorTree &RunDT,
++Iteration;
}
- if (EnablePRE) {
+ if (isPREEnabled()) {
// Fabricate val-num for dead-code in order to suppress assertion in
// performPRE().
assignValNumForDeadCode();
@@ -2682,8 +2693,8 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass {
public:
static char ID; // Pass identification, replacement for typeid
- explicit GVNLegacyPass(bool NoMemDepAnalysis = !EnableMemDep)
- : FunctionPass(ID), NoMemDepAnalysis(NoMemDepAnalysis) {
+ explicit GVNLegacyPass(bool NoMemDepAnalysis = !GVNEnableMemDep)
+ : FunctionPass(ID), Impl(GVNOptions().setMemDep(!NoMemDepAnalysis)) {
initializeGVNLegacyPassPass(*PassRegistry::getPassRegistry());
}
@@ -2698,9 +2709,9 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass {
getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F),
getAnalysis<AAResultsWrapperPass>().getAAResults(),
- NoMemDepAnalysis
- ? nullptr
- : &getAnalysis<MemoryDependenceWrapperPass>().getMemDep(),
+ Impl.isMemDepEnabled()
+ ? &getAnalysis<MemoryDependenceWrapperPass>().getMemDep()
+ : nullptr,
LIWP ? &LIWP->getLoopInfo() : nullptr,
&getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE());
}
@@ -2710,7 +2721,7 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass {
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<TargetLibraryInfoWrapperPass>();
AU.addRequired<LoopInfoWrapperPass>();
- if (!NoMemDepAnalysis)
+ if (Impl.isMemDepEnabled())
AU.addRequired<MemoryDependenceWrapperPass>();
AU.addRequired<AAResultsWrapperPass>();
@@ -2723,7 +2734,6 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass {
}
private:
- bool NoMemDepAnalysis;
GVN Impl;
};
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