[flang-commits] [PATCH] D126584: [flang] Avoid spurious warnings from reading module files

[Peter Klausler via Phabricator via flang-commits]

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When processing the literal constants of the various kinds of
INTEGER that are too large by 1 (e.g., 2147483648_4) in expression
analysis, emit a portability warning rather than a fatal error if
the literal constant appears as the operand to a unary minus, since
the folded result will be in range.  And don't emit any warning if
the negated literal is coming from a module file -- f18 wrote the
module file and the warning would simply be confusing, especially to
the programmer that wrote (-2147483647_4-1) in the first place.

Further, emit portability warnings for the canonical expressions for
infinities and NaN (-1./0., 0./0., & 1./0.), but not when they appear
in a module file, for the same reason.  The Fortran language has no
syntax for these special values so we have to emit expressions that
fold to them.

Fixes LLVM bugs https://github.com/llvm/llvm-project/issues/55086 and
https://github.com/llvm/llvm-project/issues/55081.


https://reviews.llvm.org/D126584

Files:
  flang/docs/Extensions.md
  flang/include/flang/Evaluate/common.h
  flang/include/flang/Semantics/expression.h
  flang/include/flang/Semantics/semantics.h
  flang/lib/Evaluate/fold-implementation.h
  flang/lib/Semantics/expression.cpp
  flang/lib/Semantics/mod-file.cpp
  flang/lib/Semantics/semantics.cpp
  flang/test/Semantics/dosemantics03.f90

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