[PATCH] D140868: [C] Make (c ? e1 : e2) noreturn only if both e1 and e2 are noreturn

[Arsenović Arsen via Phabricator via cfe-commits]

ArsenArsen added a comment.

noreturn is a bit special among the attributes, perhaps it'd be worthwhile 
altering the standard to say that a composite is noreturn only of all of it's 
types are.


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[PATCH] D140868: [C] Make (c ? e1 : e2) noreturn only if both e1 and e2 are noreturn

[Arsenović Arsen via Phabricator via cfe-commits]

ArsenArsen added a comment.

It'd appear that GCC merges them here:

https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/c/c-typeck.cc;h=e06f052eb46a72d3d50835330c5af975e7c52084;hb=HEAD#l708

  /* For function types do not merge const qualifiers, but drop them
 if used inconsistently.  The middle-end uses these to mark const
 and noreturn functions.  */
  if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
target_quals = (quals1 & quals2);
  else
target_quals = (quals1 | quals2);

Volatile functions are considered noreturn, as a result, this makes 
target_quals only volatile if both types are.
This behavior seems better.
Note that the same applies for [[gnu::const]] by the same logic.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D140868/new/

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