[SLP]Relax assertion to check if the input scalars were extended to

match the size of base node (PR63668).

Need to adjust the check for assert and take into account case where the
original scalars are reused and were extended to match the vector factor
of the reused SLP node.

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -952,8 +952,13 @@ static void addMask(SmallVectorImpl<int> &Mask, ArrayRef<int> SubMask,
                     bool ExtendingManyInputs = false) {
   if (SubMask.empty())
     return;
-  assert((!ExtendingManyInputs || SubMask.size() > Mask.size()) &&
-         "SubMask with many inputs support must be larger than the mask.");
+  assert(
+      (!ExtendingManyInputs || SubMask.size() > Mask.size() ||
+       // Check if input scalars were extended to match the size of other node.
+       (SubMask.size() == Mask.size() &&
+        std::all_of(std::next(Mask.begin(), Mask.size() / 2), Mask.end(),
+                    [](int Idx) { return Idx == PoisonMaskElem; }))) &&
+      "SubMask with many inputs support must be larger than the mask.");
   if (Mask.empty()) {
     Mask.append(SubMask.begin(), SubMask.end());
     return;

llvm/test/Transforms/SLPVectorizer/X86/pr63668.ll

@@ -0,0 +1,54 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
+; RUN: opt -passes=slp-vectorizer -mtriple=x86_64-unknown-linux-gnu -mcpu=znver4 -S < %s | FileCheck %s
+
+define internal i32 @testfunc() {
+; CHECK-LABEL: define internal i32 @testfunc
+; CHECK-SAME: () #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:    br label [[TMP1:%.*]]
+; CHECK:       1:
+; CHECK-NEXT:    [[TMP2:%.*]] = phi float [ 0.000000e+00, [[TMP0:%.*]] ], [ 0.000000e+00, [[TMP8:%.*]] ]
+; CHECK-NEXT:    [[TMP3:%.*]] = phi float [ 0.000000e+00, [[TMP0]] ], [ 0.000000e+00, [[TMP8]] ]
+; CHECK-NEXT:    [[TMP4:%.*]] = phi float [ 0.000000e+00, [[TMP0]] ], [ 0.000000e+00, [[TMP8]] ]
+; CHECK-NEXT:    br i1 false, label [[TMP8]], label [[TMP5:%.*]]
+; CHECK:       5:
+; CHECK-NEXT:    br i1 false, label [[TMP6:%.*]], label [[TMP8]]
+; CHECK:       6:
+; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <8 x float> zeroinitializer, i64 0
+; CHECK-NEXT:    br label [[TMP8]]
+; CHECK:       8:
+; CHECK-NEXT:    [[TMP9:%.*]] = phi float [ [[TMP7]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ 0.000000e+00, [[TMP5]] ]
+; CHECK-NEXT:    [[TMP10:%.*]] = phi float [ [[TMP2]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ [[TMP2]], [[TMP5]] ]
+; CHECK-NEXT:    [[TMP11:%.*]] = phi float [ [[TMP7]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ 0.000000e+00, [[TMP5]] ]
+; CHECK-NEXT:    [[TMP12:%.*]] = phi float [ [[TMP7]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ 0.000000e+00, [[TMP5]] ]
+; CHECK-NEXT:    [[TMP13:%.*]] = phi float [ [[TMP7]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ 0.000000e+00, [[TMP5]] ]
+; CHECK-NEXT:    [[TMP14:%.*]] = phi float [ [[TMP3]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ 0.000000e+00, [[TMP5]] ]
+; CHECK-NEXT:    [[TMP15:%.*]] = phi float [ [[TMP4]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ 0.000000e+00, [[TMP5]] ]
+; CHECK-NEXT:    [[TMP16:%.*]] = phi float [ [[TMP4]], [[TMP6]] ], [ 0.000000e+00, [[TMP1]] ], [ [[TMP3]], [[TMP5]] ]
+; CHECK-NEXT:    br label [[TMP1]]
+;
+  br label %1
+
+1:                                                ; preds = %8, %0
+  %2 = phi float [ 0.000000e+00, %0 ], [ 0.000000e+00, %8 ]
+  %3 = phi float [ 0.000000e+00, %0 ], [ 0.000000e+00, %8 ]
+  %4 = phi float [ 0.000000e+00, %0 ], [ 0.000000e+00, %8 ]
+  br i1 false, label %8, label %5
+
+5:                                                ; preds = %1
+  br i1 false, label %6, label %8
+
+6:                                                ; preds = %5
+  %7 = extractelement <8 x float> zeroinitializer, i64 0
+  br label %8
+
+8:                                                ; preds = %6, %5, %1
+  %9 = phi float [ %7, %6 ], [ 0.000000e+00, %1 ], [ 0.000000e+00, %5 ]
+  %10 = phi float [ %2, %6 ], [ 0.000000e+00, %1 ], [ %2, %5 ]
+  %11 = phi float [ %7, %6 ], [ 0.000000e+00, %1 ], [ 0.000000e+00, %5 ]
+  %12 = phi float [ %7, %6 ], [ 0.000000e+00, %1 ], [ 0.000000e+00, %5 ]
+  %13 = phi float [ %7, %6 ], [ 0.000000e+00, %1 ], [ 0.000000e+00, %5 ]
+  %14 = phi float [ %3, %6 ], [ 0.000000e+00, %1 ], [ 0.000000e+00, %5 ]
+  %15 = phi float [ %4, %6 ], [ 0.000000e+00, %1 ], [ 0.000000e+00, %5 ]
+  %16 = phi float [ %4, %6 ], [ 0.000000e+00, %1 ], [ %3, %5 ]
+  br label %1
+}