diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1150,7 +1150,12 @@
   // mempcpy(x, y, n) -> llvm.memcpy(align 1 x, align 1 y, n), x + n
   CallInst *NewCI =
       B.CreateMemCpy(Dst, Align(1), CI->getArgOperand(1), Align(1), N);
+  // Propagate attributes, but memcpy has no return value, so make sure that
+  // any return attributes are compliant.
+  // TODO: Attach return value attributes to the 1st operand to preserve them?
   NewCI->setAttributes(CI->getAttributes());
+  NewCI->removeAttributes(AttributeList::ReturnIndex,
+                          AttributeFuncs::typeIncompatible(NewCI->getType()));
   return B.CreateInBoundsGEP(B.getInt8Ty(), Dst, N);
 }
 
diff --git a/llvm/test/Transforms/InstCombine/mempcpy.ll b/llvm/test/Transforms/InstCombine/mempcpy.ll
--- a/llvm/test/Transforms/InstCombine/mempcpy.ll
+++ b/llvm/test/Transforms/InstCombine/mempcpy.ll
@@ -53,4 +53,15 @@
   ret i8* %r
 }
 
+; The original call may have attributes that can not propagate to memcpy.
+
+define i32 @PR48810() {
+; CHECK-LABEL: @PR48810(
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 1 undef, i8* align 536870912 null, i64 undef, i1 false)
+; CHECK-NEXT:    ret i32 undef
+;
+  %r = call dereferenceable(1) i8* @mempcpy(i8* undef, i8* null, i64 undef)
+  ret i32 undef
+}
+
 declare i8* @mempcpy(i8*, i8* nocapture readonly, i64)