[SLP] Protect against scalable vector users.

We started seeing a crash after 8a0bfe4 that
the user could be scalable, meaning the typesize is scalable and an implicit
convertion to uint64_t could be performed. Protect against that by making sure
the users type is not scalable.

Author: davemgreen

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -14146,6 +14146,7 @@ bool BoUpSLP::collectValuesToDemote(
                 return getTreeEntry(U) ||
                        (UserIgnoreList && UserIgnoreList->contains(U)) ||
                        (U->getType()->isSized() &&
+                        !U->getType()->isScalableTy() &&
                         DL->getTypeSizeInBits(U->getType()) <= BitWidth);
               }) &&
       !IsPotentiallyTruncated(I, BitWidth))

llvm/test/Transforms/SLPVectorizer/AArch64/scalable-external-user.ll

@@ -0,0 +1,28 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=slp-vectorizer -S | FileCheck %s
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+; Protect against a crash with scalable vector users
+
+define i1 @crash(i32 %a, i32 %b) {
+; CHECK-LABEL: @crash(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CONV_I446:%.*]] = sext i32 [[A:%.*]] to i64
+; CHECK-NEXT:    [[CMP_I618870_NOT_NOT:%.*]] = icmp ult i64 0, [[CONV_I446]]
+; CHECK-NEXT:    [[CONV_I401:%.*]] = sext i32 [[B:%.*]] to i64
+; CHECK-NEXT:    [[CMP_I407876_NOT_NOT:%.*]] = icmp ult i64 0, [[CONV_I401]]
+; CHECK-NEXT:    [[TMP0:%.*]] = tail call <vscale x 2 x i1> @llvm.aarch64.sve.whilelo.nxv2i1.i64(i64 0, i64 [[CONV_I401]])
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP_I618870_NOT_NOT]], i1 [[CMP_I407876_NOT_NOT]], i1 false
+; CHECK-NEXT:    ret i1 [[R]]
+;
+entry:
+  %conv.i446 = sext i32 %a to i64
+  %cmp.i618870.not.not = icmp ult i64 0, %conv.i446
+  %conv.i401 = sext i32 %b to i64
+  %cmp.i407876.not.not = icmp ult i64 0, %conv.i401
+  %0 = tail call <vscale x 2 x i1> @llvm.aarch64.sve.whilelo.nxv2i1.i64(i64 0, i64 %conv.i401)
+  %r = select i1 %cmp.i618870.not.not, i1 %cmp.i407876.not.not, i1 0
+  ret i1 %r
+}