[PATCH] D99892: [flang] Improve constant folding for type parameter inquiries

[Peter Klausler via Phabricator via llvm-commits]

klausler added inline comments.


================
Comment at: flang/lib/Evaluate/fold-integer.cpp:664
+  if (base) {
+    // Handling "designator%typeParam".  Get the value of the type parameter
+    // from the instantiation of the base
----------------
LEN type parameter inquiries are not safe to fold in all cases; the actual LEN parameter expression may not be constant.  Consider

  subroutine foo(n)
    type :: t(len)
    integer, len :: len
    end type t
    type(t(n)) :: x
    n = n + 1
    print *, x%len
  end

The value of x%len at its point of use needs to return the original value of the dummy argument, not its later updated value.

In general, folding type parameter inquiries can be done only for KIND= parameters and for LEN= parameters whose expressions are constant expressions.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99892/new/

https://reviews.llvm.org/D99892