[PATCH] D96791: [SLP] Double UserCost compensation for vector store of aggregate

[Anton Afanasyev via Phabricator via llvm-commits]

anton-afanasyev updated this revision to Diff 324575.
anton-afanasyev added a comment.

Cleaned pr40522.ll


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D96791/new/

https://reviews.llvm.org/D96791

Files:
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/X86/pr40522.ll


Index: llvm/test/Transforms/SLPVectorizer/X86/pr40522.ll
===================================================================
--- llvm/test/Transforms/SLPVectorizer/X86/pr40522.ll
+++ llvm/test/Transforms/SLPVectorizer/X86/pr40522.ll
@@ -30,15 +30,12 @@
 
 define void @bar(i32 %0, i32 %1, i32 %2, i32 %3, <4 x i32>* nocapture %4) {
 ; CHECK-LABEL: @bar(
-; CHECK-NEXT:    [[TMP6:%.*]] = add nsw i32 [[TMP0:%.*]], 1
-; CHECK-NEXT:    [[TMP7:%.*]] = insertelement <4 x i32> undef, i32 [[TMP6]], i32 0
-; CHECK-NEXT:    [[TMP8:%.*]] = add nsw i32 [[TMP1:%.*]], 1
-; CHECK-NEXT:    [[TMP9:%.*]] = insertelement <4 x i32> [[TMP7]], i32 [[TMP8]], i32 1
-; CHECK-NEXT:    [[TMP10:%.*]] = add nsw i32 [[TMP2:%.*]], 1
-; CHECK-NEXT:    [[TMP11:%.*]] = insertelement <4 x i32> [[TMP9]], i32 [[TMP10]], i32 2
-; CHECK-NEXT:    [[TMP12:%.*]] = add nsw i32 [[TMP3:%.*]], 1
-; CHECK-NEXT:    [[TMP13:%.*]] = insertelement <4 x i32> [[TMP11]], i32 [[TMP12]], i32 3
-; CHECK-NEXT:    store <4 x i32> [[TMP13]], <4 x i32>* [[TMP4:%.*]], align 16, [[TBAA0]]
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <4 x i32> poison, i32 [[TMP0:%.*]], i32 0
+; CHECK-NEXT:    [[TMP7:%.*]] = insertelement <4 x i32> [[TMP6]], i32 [[TMP1:%.*]], i32 1
+; CHECK-NEXT:    [[TMP8:%.*]] = insertelement <4 x i32> [[TMP7]], i32 [[TMP2:%.*]], i32 2
+; CHECK-NEXT:    [[TMP9:%.*]] = insertelement <4 x i32> [[TMP8]], i32 [[TMP3:%.*]], i32 3
+; CHECK-NEXT:    [[TMP10:%.*]] = add nsw <4 x i32> [[TMP9]], <i32 1, i32 1, i32 1, i32 1>
+; CHECK-NEXT:    store <4 x i32> [[TMP10]], <4 x i32>* [[TMP4:%.*]], align 16, [[TBAA0]]
 ; CHECK-NEXT:    ret void
 ;
   %6 = add nsw i32 %0, 1
Index: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -6288,6 +6288,18 @@
             UserCost += TTI->getVectorInstrCost(
                 Instruction::InsertElement, IE->getType(), CI->getZExtValue());
         }
+
+        // Double UserCost in case vector is used by StoreInst:
+        // the first cost to compensate ExtractCost (see above)
+        // and the second one to consider that vector is already
+        // prepared for vector store eliminating its redundant building
+        // with insert instructions.
+        for (User *U: InsertUses[I + OpsWidth - 1]->users())
+          if (isa<StoreInst>(U)) {
+              UserCost *= 2;
+              break;
+          }
+
         LLVM_DEBUG(dbgs() << "SLP: Compensate cost of users by: " << UserCost
                           << ".\n");
         Cost -= UserCost;


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