Fix off-by-one bug in AttributeList::addAttributes index handling

getParamAlignment expects an argument number, not an AttributeList
index.

Johan Englan, who works on LDC, found this bug and told me about it off
list.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303458 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed