When generating code for ISNAN(real-constant), we call
build_call_expr() and get back an expression inside a NOP_EXPR, which
is not expected, and leads to an ICE further in the middle-end. Using
STRIP_TYPE_NOPS gets rid of the problem, even though it might be
better to fix it in the middle-end. Andrew, Richard, you had ideas
about this, do you want me to keep the PR open after this workaround
is committed, and change its component to "middle-end"?

Bootstrapped and regtested, with type checking, on x86_64-linux. OK to commit?
FX


:ADDPATCH fortran: