[llvm] 83ba148 - [SLP]Include cost of the reshuffling for same nodes with resizing.

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2023-07-18T06:05:15-07:00
New Revision: 83ba148a8ae1561a32e8d6dc5209ce8d67e59a63

URL: https://github.com/llvm/llvm-project/commit/83ba148a8ae1561a32e8d6dc5209ce8d67e59a63
DIFF: https://github.com/llvm/llvm-project/commit/83ba148a8ae1561a32e8d6dc5209ce8d67e59a63.diff

LOG: [SLP]Include cost of the reshuffling for same nodes with resizing.

Need to account reshuffling, required for the reused elements in the
buildvector nodes, which are copies (perfect match) of other nodes, but
include reused elements.

Differential Revision: https://reviews.llvm.org/D149966

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    llvm/test/Transforms/SLPVectorizer/X86/crash_clear_undefs.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index b1727b31d537f0..9e179b80298177 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -7006,6 +7006,17 @@ class BoUpSLP::ShuffleCostEstimator : public BaseShuffleAnalysis {
         const TreeEntry *E2 = P2.get<const TreeEntry *>();
         if (E->Scalars.size() == E2->Scalars.size())
           CommonVF = VF = E->Scalars.size();
+      } else {
+        // P2 is empty, check that we have same node + reshuffle (if any).
+        if (E->Scalars.size() == Mask.size() && VF != Mask.size()) {
+          VF = E->Scalars.size();
+          SmallVector<int> CommonMask(Mask.begin(), Mask.end());
+          ::addMask(CommonMask, E->getCommonMask());
+          V1 = Constant::getNullValue(
+              FixedVectorType::get(E->Scalars.front()->getType(), VF));
+          return BaseShuffleAnalysis::createShuffle<InstructionCost>(
+              V1, nullptr, CommonMask, Builder);
+        }
       }
       V1 = Constant::getNullValue(
           FixedVectorType::get(E->Scalars.front()->getType(), VF));
@@ -7286,7 +7297,17 @@ BoUpSLP::getEntryCost(const TreeEntry *E, ArrayRef<Value *> VectorizedVals,
             dbgs()
             << "SLP: perfect diamond match for gather bundle that starts with "
             << *VL.front() << ".\n");
-        return 0;
+        // Restore the mask for previous partially matched values.
+        for (auto [I, V] : enumerate(E->Scalars)) {
+          if (isa<PoisonValue>(V)) {
+            Mask[I] = PoisonMaskElem;
+            continue;
+          }
+          if (Mask[I] == PoisonMaskElem)
+            Mask[I] = Entries.front()->findLaneForValue(V);
+        }
+        Estimator.add(Entries.front(), Mask);
+        return Estimator.finalize(E->ReuseShuffleIndices);
       }
       if (!Resized) {
         unsigned VF1 = Entries.front()->getVectorFactor();

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/crash_clear_undefs.ll b/llvm/test/Transforms/SLPVectorizer/X86/crash_clear_undefs.ll
index 5701ec997e7281..53667922be8018 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/crash_clear_undefs.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/crash_clear_undefs.ll
@@ -9,7 +9,7 @@ target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16
 ; YAML-NEXT:  Function:        foo
 ; YAML-NEXT:  Args:
 ; YAML-NEXT:    - String:          'SLP vectorized with cost '
-; YAML-NEXT:    - Cost:            '-6'
+; YAML-NEXT:    - Cost:            '-5'
 ; YAML-NEXT:    - String:          ' and with tree size '
 ; YAML-NEXT:    - TreeSize:        '10'
 ; YAML-NEXT:  ...