Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp
+++ lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4692,6 +4692,11 @@
           !isAccessInterleaved(&I) && !isLegalGatherOrScatter(&I))
         continue;
 
+      // If the loaded value is truncated, consider the truncated type.
+      if (isa<LoadInst>(&I) && I.hasOneUse() &&
+         (isa<TruncInst>(*I.user_begin()) || isa<FPTruncInst>(*I.user_begin())))
+        T = (*I.user_begin())->getType();
+
       MinWidth = std::min(MinWidth,
                           (unsigned)DL.getTypeSizeInBits(T->getScalarType()));
       MaxWidth = std::max(MaxWidth,
Index: test/Transforms/LoopVectorize/SystemZ/maxVF_truncload.ll
===================================================================
--- /dev/null
+++ test/Transforms/LoopVectorize/SystemZ/maxVF_truncload.ll
@@ -0,0 +1,26 @@
+; RUN: opt < %s -mtriple=s390x-unknown-linux -mcpu=z13 -o - -loop-vectorize \
+; RUN:  -debug-only=loop-vectorize 2>&1 | FileCheck %s
+; REQUIRES: asserts
+;
+; CHECK: LV: The Smallest and Widest types: 32 / 32 bits.
+; CHECK: LV: Selecting VF: 4.
+
+define void @fun(i64 %n, i32 %v, i64* %ptr, i32* %dst) {
+entry:
+  br label %for.body
+
+for.body:
+  %i = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
+  %addr = getelementptr inbounds i64, i64* %ptr, i64 %i
+  %l64 = load i64, i64* %addr
+  %conv = trunc i64 %l64 to i32
+  %addr1 = getelementptr inbounds i32, i32* %dst, i64 %i
+  store i32 %conv, i32* %addr1
+  %iv.next = add nuw nsw i64 %i, 1
+  %cmp = icmp slt i64 %iv.next, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:
+  ret void
+}
+