[llvm] [SLP][REVEC] reorderNodeWithReuses should not be called if all users of a TreeEntry are ShuffleVectorInst. (PR #118260)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-vectorizers

@llvm/pr-subscribers-llvm-transforms

Author: Han-Kuan Chen (HanKuanChen)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/118260.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp (+17) 
- (modified) llvm/test/Transforms/SLPVectorizer/revec.ll (+34) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 04755102643364..74f5df11ed6a9e 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -6073,6 +6073,23 @@ void BoUpSLP::reorderTopToBottom() {
                                      TE->Scalars.size();
                         }) &&
                  "All users must be of VF size.");
+          if (SLPReVec) {
+            assert(SLPReVec && "Only supported by REVEC.");
+            // ShuffleVectorInst does not do reorderOperands (and it should not
+            // because ShuffleVectorInst supports only a limited set of
+            // patterns). Only do reorderNodeWithReuses if all of the users are
+            // not ShuffleVectorInst.
+            if (all_of(TE->UserTreeIndices, [&](const EdgeInfo &EI) {
+                  return isa<ShuffleVectorInst>(EI.UserTE->getMainOp());
+                }))
+              continue;
+            assert(all_of(TE->UserTreeIndices,
+                          [&](const EdgeInfo &EI) {
+                            return !isa<ShuffleVectorInst>(
+                                EI.UserTE->getMainOp());
+                          }) &&
+                   "Does not know how to reorder.");
+          }
           // Update ordering of the operands with the smaller VF than the given
           // one.
           reorderNodeWithReuses(*TE, Mask);
diff --git a/llvm/test/Transforms/SLPVectorizer/revec.ll b/llvm/test/Transforms/SLPVectorizer/revec.ll
index b160c0174c0a76..ce13f478d38116 100644
--- a/llvm/test/Transforms/SLPVectorizer/revec.ll
+++ b/llvm/test/Transforms/SLPVectorizer/revec.ll
@@ -447,3 +447,37 @@ for.end.loopexit:
   store <4 x i32> %4, ptr %out2, align 4
   ret void
 }
+
+define void @test14(<8 x i1> %0) {
+; CHECK-LABEL: @test14(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP1:%.*]] = call <16 x i1> @llvm.vector.insert.v16i1.v8i1(<16 x i1> poison, <8 x i1> [[TMP0:%.*]], i64 0)
+; CHECK-NEXT:    [[TMP2:%.*]] = shufflevector <16 x i1> [[TMP1]], <16 x i1> poison, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+; CHECK-NEXT:    [[TMP3:%.*]] = sext <16 x i1> [[TMP2]] to <16 x i16>
+; CHECK-NEXT:    [[TMP4:%.*]] = shufflevector <16 x i16> [[TMP3]], <16 x i16> poison, <32 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+; CHECK-NEXT:    [[TMP5:%.*]] = shufflevector <16 x i16> [[TMP3]], <16 x i16> poison, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+; CHECK-NEXT:    [[TMP6:%.*]] = shufflevector <16 x i16> [[TMP3]], <16 x i16> poison, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 4, i32 5, i32 6, i32 7>
+; CHECK-NEXT:    br label [[FOR_END_LOOPEXIT:%.*]]
+; CHECK:       for.end.loopexit:
+; CHECK-NEXT:    [[TMP7:%.*]] = phi <16 x i16> [ [[TMP6]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[TMP8:%.*]] = call <4 x i16> @llvm.vector.extract.v4i16.v16i16(<16 x i16> [[TMP7]], i64 12)
+; CHECK-NEXT:    [[OR0:%.*]] = or <4 x i16> [[TMP8]], zeroinitializer
+; CHECK-NEXT:    ret void
+;
+entry:
+  %sext0 = sext <8 x i1> %0 to <8 x i16>
+  %sext1 = sext <8 x i1> %0 to <8 x i16>
+  %1 = shufflevector <8 x i16> %sext0, <8 x i16> zeroinitializer, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
+  %2 = shufflevector <8 x i16> %sext0, <8 x i16> zeroinitializer, <4 x i32> <i32 4, i32 5, i32 6, i32 7>
+  %3 = shufflevector <8 x i16> %sext1, <8 x i16> zeroinitializer, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
+  %4 = shufflevector <8 x i16> %sext1, <8 x i16> zeroinitializer, <4 x i32> <i32 4, i32 5, i32 6, i32 7>
+  br label %for.end.loopexit
+
+for.end.loopexit:
+  %phi0 = phi <4 x i16> [ %1, %entry ]
+  %phi1 = phi <4 x i16> [ %2, %entry ]
+  %phi2 = phi <4 x i16> [ %3, %entry ]
+  %phi3 = phi <4 x i16> [ %4, %entry ]
+  %or0 = or <4 x i16> %phi1, zeroinitializer
+  ret void
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/118260