On Wed, 21 Jul 2021, Jakub Jelinek via Gcc-patches wrote: > I wonder if instead when trying to wrap > C_MAYBE_CONST_EXPR into a VIEW_CONVERT_EXPR we shouldn't be > removing that C_MAYBE_CONST_EXPR and perhaps adding it around the > VIEW_CONVERT_EXPR. E.g. various routines in c/c-typeck.c like > build_unary_op remember int_operands, remove_c_maybe_const_expr > and at the end note_integer_operands. > > If Joseph thinks it is ok to have C_MAYBE_CONST_EXPR inside of > VCE, then the patch looks good to me.
There are specific cases when a C_MAYBE_CONST_EXPR mustn't appear inside another expression: any case where the inner expression is required to be fully folded (this implies nested C_MAYBE_CONST_EXPR aren't allowed) and any case where the expression might appear (possibly unevaluated) in an integer constant expression (any C_MAYBE_CONST_EXPR noting that needs to be at top level). If the expressions involved here can never appear in an integer constant expression and do not need to be fully folded, I think it's OK to have C_MAYBE_CONST_EXPR inside VIEW_CONVERT_EXPR. -- Joseph S. Myers jos...@codesourcery.com
