[llvm] [LoopVectorize] Move checking for OptForSize into the cost model (NFC) (PR #130752)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-vectorizers

Author: John Brawn (john-brawn-arm)

<details>
<summary>Changes</summary>

Move OptForSizeBasedOnProfile into the cost model and rename it to OptForSize, as shouldOptimizeForSize checks both the function attribute and profile. This being done in preparation for OptForSize being used in the cost model.

---
Full diff: https://github.com/llvm/llvm-project/pull/130752.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+16-17) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 02aa21e33bf4f..f0f85c706866b 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -494,12 +494,7 @@ class InnerLoopVectorizer {
         MinProfitableTripCount(MinProfitableTripCount), UF(UnrollFactor),
         Builder(PSE.getSE()->getContext()), Legal(LVL), Cost(CM), BFI(BFI),
         PSI(PSI), RTChecks(RTChecks), Plan(Plan),
-        VectorPHVPB(Plan.getEntry()->getSingleSuccessor()) {
-    // Query this against the original loop and save it here because the profile
-    // of the original loop header may change as the transformation happens.
-    OptForSizeBasedOnProfile = llvm::shouldOptimizeForSize(
-        OrigLoop->getHeader(), PSI, BFI, PGSOQueryType::IRPass);
-  }
+        VectorPHVPB(Plan.getEntry()->getSingleSuccessor()) {}
 
   virtual ~InnerLoopVectorizer() = default;
 
@@ -672,10 +667,6 @@ class InnerLoopVectorizer {
   BlockFrequencyInfo *BFI;
   ProfileSummaryInfo *PSI;
 
-  // Whether this loop should be optimized for size based on profile guided size
-  // optimizatios.
-  bool OptForSizeBasedOnProfile;
-
   /// Structure to hold information about generated runtime checks, responsible
   /// for cleaning the checks, if vectorization turns out unprofitable.
   GeneratedRTChecks &RTChecks;
@@ -987,13 +978,18 @@ class LoopVectorizationCostModel {
                              AssumptionCache *AC,
                              OptimizationRemarkEmitter *ORE, const Function *F,
                              const LoopVectorizeHints *Hints,
-                             InterleavedAccessInfo &IAI)
+                             InterleavedAccessInfo &IAI,
+                             ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI)
       : ScalarEpilogueStatus(SEL), TheLoop(L), PSE(PSE), LI(LI), Legal(Legal),
         TTI(TTI), TLI(TLI), DB(DB), AC(AC), ORE(ORE), TheFunction(F),
         Hints(Hints), InterleaveInfo(IAI) {
     if (TTI.supportsScalableVectors() || ForceTargetSupportsScalableVectors)
       initializeVScaleForTuning();
     CostKind = F->hasMinSize() ? TTI::TCK_CodeSize : TTI::TCK_RecipThroughput;
+    // Query this against the original loop and save it here because the profile
+    // of the original loop header may change as the transformation happens.
+    OptForSize = llvm::shouldOptimizeForSize(L->getHeader(), PSI, BFI,
+                                             PGSOQueryType::IRPass);
   }
 
   /// \return An upper bound for the vectorization factors (both fixed and
@@ -1830,6 +1826,10 @@ class LoopVectorizationCostModel {
 
   /// The kind of cost that we are calculating
   TTI::TargetCostKind CostKind;
+
+  /// Whether this loop should be optimized for size based on function attribute
+  /// or profile information.
+  bool OptForSize;
 };
 } // end namespace llvm
 
@@ -2602,9 +2602,8 @@ BasicBlock *InnerLoopVectorizer::emitSCEVChecks(BasicBlock *Bypass) {
   if (!SCEVCheckBlock)
     return nullptr;
 
-  assert(!(SCEVCheckBlock->getParent()->hasOptSize() ||
-           (OptForSizeBasedOnProfile &&
-            Cost->Hints->getForce() != LoopVectorizeHints::FK_Enabled)) &&
+  assert((!Cost->OptForSize ||
+          Cost->Hints->getForce() == LoopVectorizeHints::FK_Enabled) &&
          "Cannot SCEV check stride or overflow when optimizing for size");
   assert(!LoopBypassBlocks.empty() &&
          "Should already be a bypass block due to iteration count check");
@@ -2629,7 +2628,7 @@ BasicBlock *InnerLoopVectorizer::emitMemRuntimeChecks(BasicBlock *Bypass) {
   assert((!EnableVPlanNativePath || OrigLoop->begin() == OrigLoop->end()) &&
          "Runtime checks are not supported for outer loops yet");
 
-  if (MemCheckBlock->getParent()->hasOptSize() || OptForSizeBasedOnProfile) {
+  if (Cost->OptForSize) {
     assert(Cost->Hints->getForce() == LoopVectorizeHints::FK_Enabled &&
            "Cannot emit memory checks when optimizing for size, unless forced "
            "to vectorize.");
@@ -10083,7 +10082,7 @@ static bool processLoopInVPlanNativePath(
       getScalarEpilogueLowering(F, L, Hints, PSI, BFI, TTI, TLI, *LVL, &IAI);
 
   LoopVectorizationCostModel CM(SEL, L, PSE, LI, LVL, *TTI, TLI, DB, AC, ORE, F,
-                                &Hints, IAI);
+                                &Hints, IAI, PSI, BFI);
   // Use the planner for outer loop vectorization.
   // TODO: CM is not used at this point inside the planner. Turn CM into an
   // optional argument if we don't need it in the future.
@@ -10620,7 +10619,7 @@ bool LoopVectorizePass::processLoop(Loop *L) {
 
   // Use the cost model.
   LoopVectorizationCostModel CM(SEL, L, PSE, LI, &LVL, *TTI, TLI, DB, AC, ORE,
-                                F, &Hints, IAI);
+                                F, &Hints, IAI, PSI, BFI);
   // Use the planner for vectorization.
   LoopVectorizationPlanner LVP(L, LI, DT, TLI, *TTI, &LVL, CM, IAI, PSE, Hints,
                                ORE);

``````````

</details>


https://github.com/llvm/llvm-project/pull/130752