[PATCH] D122819: [FuncSpec] Cache code metrics for analyzed functions.
Alexandros Lamprineas via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 31 07:38:12 PDT 2022
labrinea created this revision.
labrinea added reviewers: ChuanqiXu, SjoerdMeijer.
Herald added subscribers: snehasish, ormris, hiraditya.
Herald added a project: All.
labrinea requested review of this revision.
Herald added a project: LLVM.
This isn't expected to reduce compilation times as `max-iters` is set to one by default, but it helps with recursive functions that require higher iteration counts.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D122819
Files:
llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
Index: llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
===================================================================
--- llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
+++ llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
@@ -21,8 +21,6 @@
// but that's off by default under an option.
// - The cost-model could be further looked into (it mainly focuses on inlining
// benefits),
-// - We are not yet caching analysis results, but profiling and checking where
-// extra compile time is spent didn't suggest this to be a problem.
//
// Ideas:
// - With a function specialization attribute for arguments, we could have
@@ -281,6 +279,7 @@
SmallPtrSet<Function *, 4> SpecializedFuncs;
SmallPtrSet<Function *, 4> FullySpecialized;
SmallVector<Instruction *> ReplacedWithConstant;
+ DenseMap<Function *, CodeMetrics> FunctionMetrics;
public:
FunctionSpecializer(SCCPSolver &Solver,
@@ -390,6 +389,19 @@
// also in the cost model.
unsigned NbFunctionsSpecialized = 0;
+ // Cache the CodeMetrics for function \p F.
+ void analyzeFunction(Function *F) {
+ SmallPtrSet<const Value *, 32> EphValues;
+ CodeMetrics::collectEphemeralValues(F, &(GetAC)(*F), EphValues);
+ CodeMetrics &Metrics = FunctionMetrics[F];
+ for (BasicBlock &BB : *F)
+ Metrics.analyzeBasicBlock(&BB, (GetTTI)(*F), EphValues);
+
+ LLVM_DEBUG(dbgs() << "FnSpecialization: Code size of function "
+ << F->getName() << " is " << Metrics.NumInsts
+ << " instructions\n");
+ }
+
/// Clone the function \p F and remove the ssa_copy intrinsics added by
/// the SCCPSolver in the cloned version.
Function *cloneCandidateFunction(Function *F, ValueToValueMapTy &Mappings) {
@@ -528,12 +540,10 @@
/// Compute and return the cost of specializing function \p F.
InstructionCost getSpecializationCost(Function *F) {
- // Compute the code metrics for the function.
- SmallPtrSet<const Value *, 32> EphValues;
- CodeMetrics::collectEphemeralValues(F, &(GetAC)(*F), EphValues);
- CodeMetrics Metrics;
- for (BasicBlock &BB : *F)
- Metrics.analyzeBasicBlock(&BB, (GetTTI)(*F), EphValues);
+ auto I = FunctionMetrics.insert({F, CodeMetrics()});
+ CodeMetrics &Metrics = I.first->second;
+ if (I.second)
+ analyzeFunction(F);
// If the code metrics reveal that we shouldn't duplicate the function, we
// shouldn't specialize it. Set the specialization cost to Invalid.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D122819.419448.patch
Type: text/x-patch
Size: 2490 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220331/fefdf41f/attachment.bin>
More information about the llvm-commits
mailing list