[llvm] 59ff9d3 - [SLP]Fix PR61554: use of missing vectorized value in buildvector nodes.

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2023-03-20T12:05:26-07:00
New Revision: 59ff9d3777701ebbe6a59ab2edb8792ef3d2873f

URL: https://github.com/llvm/llvm-project/commit/59ff9d3777701ebbe6a59ab2edb8792ef3d2873f
DIFF: https://github.com/llvm/llvm-project/commit/59ff9d3777701ebbe6a59ab2edb8792ef3d2873f.diff

LOG: [SLP]Fix PR61554: use of missing vectorized value in buildvector nodes.

If the buildvector node matches the vector node, it reuse the vector
value from this vector node, but its VectorizedValue field is not
updated. Need to update this field to avoid misses during the analysis
of the reused gather/buildvector nodes.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    llvm/test/Transforms/SLPVectorizer/X86/reused-buildvector-matching-vectorized-node.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 9da2fd4bbabe5..ba8e04538d383 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -9352,6 +9352,21 @@ Value *BoUpSLP::vectorizeOperand(TreeEntry *E, unsigned NodeIdx) {
           V = FinalShuffle(V, UniformMask);
         }
       }
+      // Need to update the operand gather node, if actually the operand is not a
+      // vectorized node, but the buildvector/gather node, which matches one of
+      // the vectorized nodes.
+      if (find_if(VE->UserTreeIndices, [&](const EdgeInfo &EI) {
+            return EI.UserTE == E && EI.EdgeIdx == NodeIdx;
+          }) == VE->UserTreeIndices.end()) {
+        auto *It = find_if(
+            VectorizableTree, [&](const std::unique_ptr<TreeEntry> &TE) {
+              return TE->State == TreeEntry::NeedToGather &&
+                     TE->UserTreeIndices.front().UserTE == E &&
+                     TE->UserTreeIndices.front().EdgeIdx == NodeIdx;
+            });
+        assert(It != VectorizableTree.end() && "Expected gather node operand.");
+        (*It)->VectorizedValue = V;
+      }
       return V;
     }
   }

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/reused-buildvector-matching-vectorized-node.ll b/llvm/test/Transforms/SLPVectorizer/X86/reused-buildvector-matching-vectorized-node.ll
index d250fcfe5bf80..2b425ee624700 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/reused-buildvector-matching-vectorized-node.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/reused-buildvector-matching-vectorized-node.ll
@@ -10,7 +10,7 @@ define void @blam(ptr %arg, double %load2, i1 %fcmp3) {
 ; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <2 x i1> poison, i1 [[FCMP3]], i32 0
 ; CHECK-NEXT:    [[TMP2:%.*]] = shufflevector <2 x i1> [[TMP1]], <2 x i1> poison, <2 x i32> zeroinitializer
 ; CHECK-NEXT:    [[TMP3:%.*]] = select <2 x i1> [[TMP2]], <2 x double> zeroinitializer, <2 x double> [[TMP0]]
-; CHECK-NEXT:    [[TMP4:%.*]] = load <2 x double>, ptr poison, align 16
+; CHECK-NEXT:    [[TMP4:%.*]] = insertelement <2 x double> [[TMP0]], double [[LOAD2]], i32 0
 ; CHECK-NEXT:    [[TMP5:%.*]] = fcmp olt <2 x double> [[TMP4]], zeroinitializer
 ; CHECK-NEXT:    [[TMP6:%.*]] = select <2 x i1> [[TMP5]], <2 x double> zeroinitializer, <2 x double> [[TMP0]]
 ; CHECK-NEXT:    [[TMP7:%.*]] = fcmp olt <2 x double> [[TMP3]], zeroinitializer