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

Author: HanKuanChen

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(none_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);

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
+}