Fixes a compiler assert on passing a compile time integer to atomic builtins.
Assert introduced in D61522
Function changed from ->bool to ->Optional in D76646
Simplifies call sites to getIntegerConstantExpr to elide the now-redundant
isValueDependent checks.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D112159
which they do. This avoids all of the default argument promotions that
we (1) don't want, and (2) undo during that custom type checking, and
makes sure that we don't run into trouble during template
instantiation. Fixes PR11320.
llvm-svn: 144110