[SLP]Fix PR79743: Check that all users are demoted before trying to

demote the tree entry.

Need to check if all user nodes are marked for demotion before demoting
the node. Otherwise, some data info might be lost after vectorization.

Author: alexey-bataev

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -13323,6 +13323,20 @@ void BoUpSLP::computeMinimumValueSizes() {
                           Visited);
   }
 
+  // Check that all users are marked for demotion.
+  DenseSet<Value *> Demoted(ToDemote.begin(), ToDemote.end());
+  DenseSet<const TreeEntry *> Visited;
+  for (Value *V: ToDemote) {
+    const TreeEntry *TE = getTreeEntry(V);
+    assert(TE && "Expected vectorized scalar.");
+    if (!Visited.insert(TE).second)
+      continue;
+    if (!all_of(TE->UserTreeIndices, [&](const EdgeInfo &EI) {
+          return all_of(EI.UserTE->Scalars,
+                        [&](Value *V) { return Demoted.contains(V); });
+        }))
+      return;
+  }
   // Finally, map the values we can demote to the maximum bit with we computed.
   for (auto *Scalar : ToDemote) {
     auto *TE = getTreeEntry(Scalar);

llvm/test/Transforms/SLPVectorizer/X86/minbitwidth-node-with-multi-users.ll

@@ -10,20 +10,16 @@ define void @test() {
 ; CHECK-NEXT:    [[TMP3:%.*]] = select i1 false, i32 0, i32 0
 ; CHECK-NEXT:    [[TMP4:%.*]] = insertelement <4 x i8> <i8 poison, i8 0, i8 poison, i8 poison>, i8 [[TMP1]], i32 0
 ; CHECK-NEXT:    [[TMP5:%.*]] = shufflevector <4 x i8> [[TMP4]], <4 x i8> poison, <4 x i32> <i32 0, i32 0, i32 0, i32 1>
-; CHECK-NEXT:    [[TMP6:%.*]] = trunc <4 x i8> [[TMP5]] to <4 x i1>
-; CHECK-NEXT:    [[TMP7:%.*]] = zext <4 x i1> [[TMP6]] to <4 x i32>
-; CHECK-NEXT:    [[TMP8:%.*]] = shufflevector <4 x i8> [[TMP4]], <4 x i8> poison, <4 x i32> zeroinitializer
-; CHECK-NEXT:    [[TMP9:%.*]] = or <4 x i8> [[TMP8]], zeroinitializer
-; CHECK-NEXT:    [[TMP10:%.*]] = sext <4 x i8> [[TMP9]] to <4 x i32>
-; CHECK-NEXT:    [[TMP11:%.*]] = zext <4 x i1> [[TMP6]] to <4 x i32>
-; CHECK-NEXT:    [[TMP12:%.*]] = or <4 x i32> zeroinitializer, [[TMP11]]
-; CHECK-NEXT:    [[TMP13:%.*]] = icmp eq <4 x i32> [[TMP10]], [[TMP12]]
-; CHECK-NEXT:    [[TMP14:%.*]] = shufflevector <4 x i32> <i32 0, i32 0, i32 poison, i32 0>, <4 x i32> [[TMP7]], <4 x i32> <i32 0, i32 1, i32 6, i32 3>
-; CHECK-NEXT:    [[TMP15:%.*]] = select <4 x i1> [[TMP13]], <4 x i32> [[TMP14]], <4 x i32> zeroinitializer
-; CHECK-NEXT:    [[TMP16:%.*]] = trunc <4 x i32> [[TMP15]] to <4 x i1>
-; CHECK-NEXT:    [[TMP17:%.*]] = call i1 @llvm.vector.reduce.and.v4i1(<4 x i1> [[TMP16]])
-; CHECK-NEXT:    [[TMP18:%.*]] = zext i1 [[TMP17]] to i32
-; CHECK-NEXT:    [[OP_RDX:%.*]] = and i32 0, [[TMP18]]
+; CHECK-NEXT:    [[TMP6:%.*]] = sext <4 x i8> [[TMP5]] to <4 x i32>
+; CHECK-NEXT:    [[TMP7:%.*]] = shufflevector <4 x i8> [[TMP4]], <4 x i8> poison, <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP8:%.*]] = or <4 x i8> [[TMP7]], zeroinitializer
+; CHECK-NEXT:    [[TMP9:%.*]] = sext <4 x i8> [[TMP8]] to <4 x i32>
+; CHECK-NEXT:    [[TMP10:%.*]] = or <4 x i32> zeroinitializer, [[TMP6]]
+; CHECK-NEXT:    [[TMP11:%.*]] = icmp eq <4 x i32> [[TMP9]], [[TMP10]]
+; CHECK-NEXT:    [[TMP12:%.*]] = shufflevector <4 x i32> [[TMP6]], <4 x i32> <i32 0, i32 0, i32 poison, i32 0>, <4 x i32> <i32 4, i32 5, i32 2, i32 7>
+; CHECK-NEXT:    [[TMP13:%.*]] = select <4 x i1> [[TMP11]], <4 x i32> [[TMP12]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP14:%.*]] = call i32 @llvm.vector.reduce.and.v4i32(<4 x i32> [[TMP13]])
+; CHECK-NEXT:    [[OP_RDX:%.*]] = and i32 0, [[TMP14]]
 ; CHECK-NEXT:    store i32 [[OP_RDX]], ptr null, align 4
 ; CHECK-NEXT:    ret void
 ;