[llvm] 7a0f75c - Reapply "[GVN] MemorySSA for GVN: add optional `AllowMemorySSA`"
Antonio Frighetto via llvm-commits
llvm-commits at lists.llvm.org
Tue Jan 14 01:07:39 PST 2025
Author: Antonio Frighetto
Date: 2025-01-14T10:03:47+01:00
New Revision: 7a0f75c7385e971b84f05da2e48c138dc40f2b3b
URL: https://github.com/llvm/llvm-project/commit/7a0f75c7385e971b84f05da2e48c138dc40f2b3b
DIFF: https://github.com/llvm/llvm-project/commit/7a0f75c7385e971b84f05da2e48c138dc40f2b3b.diff
LOG: Reapply "[GVN] MemorySSA for GVN: add optional `AllowMemorySSA`"
Original commit: eb63cd62a4a1907dbd58f12660efd8244e7d81e9
Previously reverted due to non-negligible compile-time impact in
stage1-ReleaseLTO-g scenario. The issue has been addressed by
always reusing previously computed MemorySSA results, and request
new ones only when `isMemorySSAEnabled` is set.
Co-authored-by: Momchil Velikov <momchil.velikov at arm.com>
Added:
Modified:
llvm/include/llvm/Transforms/Scalar/GVN.h
llvm/lib/Passes/PassBuilder.cpp
llvm/lib/Passes/PassRegistry.def
llvm/lib/Transforms/Scalar/GVN.cpp
llvm/test/Other/new-pm-print-pipeline.ll
Removed:
################################################################################
diff --git a/llvm/include/llvm/Transforms/Scalar/GVN.h b/llvm/include/llvm/Transforms/Scalar/GVN.h
index be6c0ec5edab07..c8be390799836e 100644
--- a/llvm/include/llvm/Transforms/Scalar/GVN.h
+++ b/llvm/include/llvm/Transforms/Scalar/GVN.h
@@ -77,6 +77,7 @@ struct GVNOptions {
std::optional<bool> AllowLoadInLoopPRE;
std::optional<bool> AllowLoadPRESplitBackedge;
std::optional<bool> AllowMemDep;
+ std::optional<bool> AllowMemorySSA;
GVNOptions() = default;
@@ -108,6 +109,12 @@ struct GVNOptions {
AllowMemDep = MemDep;
return *this;
}
+
+ /// Enables or disables use of MemorySSA.
+ GVNOptions &setMemorySSA(bool MemSSA) {
+ AllowMemorySSA = MemSSA;
+ return *this;
+ }
};
/// The core GVN pass object.
@@ -144,6 +151,7 @@ class GVNPass : public PassInfoMixin<GVNPass> {
bool isLoadInLoopPREEnabled() const;
bool isLoadPRESplitBackedgeEnabled() const;
bool isMemDepEnabled() const;
+ bool isMemorySSAEnabled() 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
@@ -383,9 +391,8 @@ class GVNPass : public PassInfoMixin<GVNPass> {
void assignBlockRPONumber(Function &F);
};
-/// Create a legacy GVN pass. This also allows parameterizing whether or not
-/// MemDep is enabled.
-FunctionPass *createGVNPass(bool NoMemDepAnalysis = false);
+/// Create a legacy GVN pass.
+FunctionPass *createGVNPass();
/// A simple and fast domtree-based GVN pass to hoist common expressions
/// from sibling branches.
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index f923d5aabe0a0e..94782547325ed1 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -1042,6 +1042,8 @@ Expected<GVNOptions> parseGVNOptions(StringRef Params) {
Result.setLoadPRESplitBackedge(Enable);
} else if (ParamName == "memdep") {
Result.setMemDep(Enable);
+ } else if (ParamName == "memoryssa") {
+ Result.setMemorySSA(Enable);
} else {
return make_error<StringError>(
formatv("invalid GVN pass parameter '{0}' ", ParamName).str(),
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 1021d7fcd92474..a93a995655a147 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -526,7 +526,7 @@ FUNCTION_PASS_WITH_PARAMS(
"gvn", "GVNPass", [](GVNOptions Opts) { return GVNPass(Opts); },
parseGVNOptions,
"no-pre;pre;no-load-pre;load-pre;no-split-backedge-load-pre;"
- "split-backedge-load-pre;no-memdep;memdep")
+ "split-backedge-load-pre;no-memdep;memdep;no-memoryssa;memoryssa")
FUNCTION_PASS_WITH_PARAMS(
"hardware-loops", "HardwareLoopsPass",
[](HardwareLoopOptions Opts) { return HardwareLoopsPass(Opts); },
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index 229fffe92b99c0..31af2d8a617b63 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -113,6 +113,8 @@ static cl::opt<bool>
GVNEnableSplitBackedgeInLoadPRE("enable-split-backedge-in-load-pre",
cl::init(false));
static cl::opt<bool> GVNEnableMemDep("enable-gvn-memdep", cl::init(true));
+static cl::opt<bool> GVNEnableMemorySSA("enable-gvn-memoryssa",
+ cl::init(false));
static cl::opt<uint32_t> MaxNumDeps(
"gvn-max-num-deps", cl::Hidden, cl::init(100),
@@ -820,6 +822,10 @@ bool GVNPass::isMemDepEnabled() const {
return Options.AllowMemDep.value_or(GVNEnableMemDep);
}
+bool GVNPass::isMemorySSAEnabled() const {
+ return Options.AllowMemorySSA.value_or(GVNEnableMemorySSA);
+}
+
PreservedAnalyses GVNPass::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
@@ -833,6 +839,11 @@ PreservedAnalyses GVNPass::run(Function &F, FunctionAnalysisManager &AM) {
isMemDepEnabled() ? &AM.getResult<MemoryDependenceAnalysis>(F) : nullptr;
auto &LI = AM.getResult<LoopAnalysis>(F);
auto *MSSA = AM.getCachedResult<MemorySSAAnalysis>(F);
+ if (isMemorySSAEnabled() && !MSSA) {
+ assert(!MemDep &&
+ "On-demand computation of MemSSA implies that MemDep is disabled!");
+ MSSA = &AM.getResult<MemorySSAAnalysis>(F);
+ }
auto &ORE = AM.getResult<OptimizationRemarkEmitterAnalysis>(F);
bool Changed = runImpl(F, AC, DT, TLI, AA, MemDep, LI, &ORE,
MSSA ? &MSSA->getMSSA() : nullptr);
@@ -861,7 +872,9 @@ void GVNPass::printPipeline(
OS << (*Options.AllowLoadPRESplitBackedge ? "" : "no-")
<< "split-backedge-load-pre;";
if (Options.AllowMemDep != std::nullopt)
- OS << (*Options.AllowMemDep ? "" : "no-") << "memdep";
+ OS << (*Options.AllowMemDep ? "" : "no-") << "memdep;";
+ if (Options.AllowMemorySSA != std::nullopt)
+ OS << (*Options.AllowMemorySSA ? "" : "no-") << "memoryssa";
OS << '>';
}
@@ -3293,8 +3306,11 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass {
public:
static char ID; // Pass identification, replacement for typeid
- explicit GVNLegacyPass(bool NoMemDepAnalysis = !GVNEnableMemDep)
- : FunctionPass(ID), Impl(GVNOptions().setMemDep(!NoMemDepAnalysis)) {
+ explicit GVNLegacyPass(bool MemDepAnalysis = GVNEnableMemDep,
+ bool MemSSAAnalysis = GVNEnableMemorySSA)
+ : FunctionPass(ID), Impl(GVNOptions()
+ .setMemDep(MemDepAnalysis)
+ .setMemorySSA(MemSSAAnalysis)) {
initializeGVNLegacyPassPass(*PassRegistry::getPassRegistry());
}
@@ -3303,6 +3319,9 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass {
return false;
auto *MSSAWP = getAnalysisIfAvailable<MemorySSAWrapperPass>();
+ if (Impl.isMemorySSAEnabled() && !MSSAWP)
+ MSSAWP = &getAnalysis<MemorySSAWrapperPass>();
+
return Impl.runImpl(
F, getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F),
getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
@@ -3330,6 +3349,8 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass {
AU.addPreserved<LoopInfoWrapperPass>();
AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
AU.addPreserved<MemorySSAWrapperPass>();
+ if (Impl.isMemorySSAEnabled())
+ AU.addRequired<MemorySSAWrapperPass>();
}
private:
@@ -3341,6 +3362,7 @@ char GVNLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(GVNLegacyPass, "gvn", "Global Value Numbering", false, false)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
@@ -3349,6 +3371,4 @@ INITIALIZE_PASS_DEPENDENCY(OptimizationRemarkEmitterWrapperPass)
INITIALIZE_PASS_END(GVNLegacyPass, "gvn", "Global Value Numbering", false, false)
// The public interface to this file...
-FunctionPass *llvm::createGVNPass(bool NoMemDepAnalysis) {
- return new GVNLegacyPass(NoMemDepAnalysis);
-}
+FunctionPass *llvm::createGVNPass() { return new GVNLegacyPass(); }
diff --git a/llvm/test/Other/new-pm-print-pipeline.ll b/llvm/test/Other/new-pm-print-pipeline.ll
index 9016473b36ba44..eb3ffe3a098dda 100644
--- a/llvm/test/Other/new-pm-print-pipeline.ll
+++ b/llvm/test/Other/new-pm-print-pipeline.ll
@@ -31,8 +31,8 @@
; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(loop-unroll<>,loop-unroll<partial;peeling;runtime;upperbound;profile-peeling;full-unroll-max=5;O1>,loop-unroll<no-partial;no-peeling;no-runtime;no-upperbound;no-profile-peeling;full-unroll-max=7;O1>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-10
; CHECK-10: function(loop-unroll<O2>,loop-unroll<partial;peeling;runtime;upperbound;profile-peeling;full-unroll-max=5;O1>,loop-unroll<no-partial;no-peeling;no-runtime;no-upperbound;no-profile-peeling;full-unroll-max=7;O1>)
-; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(gvn<>,gvn<pre;load-pre;split-backedge-load-pre;memdep>,gvn<no-pre;no-load-pre;no-split-backedge-load-pre;no-memdep>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-11
-; CHECK-11: function(gvn<>,gvn<pre;load-pre;split-backedge-load-pre;memdep>,gvn<no-pre;no-load-pre;no-split-backedge-load-pre;no-memdep>)
+; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(gvn<>,gvn<pre;load-pre;split-backedge-load-pre;memdep;memoryssa>,gvn<no-pre;no-load-pre;no-split-backedge-load-pre;no-memdep;no-memoryssa>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-11
+; CHECK-11: function(gvn<>,gvn<pre;load-pre;split-backedge-load-pre;memdep;memoryssa>,gvn<no-pre;no-load-pre;no-split-backedge-load-pre;no-memdep;no-memoryssa>)
; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(early-cse<>,early-cse<memssa>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-12
; CHECK-12: function(early-cse<>,early-cse<memssa>)
More information about the llvm-commits
mailing list