Excerpts from Kewen.Lin's message of Juni 3, 2024 10:57 am: > Hi Iain, > > on 2024/6/3 16:40, Iain Buclaw wrote: >> Excerpts from Kewen Lin's message of Juni 3, 2024 5:00 am: >>> Joseph pointed out "floating types should have their mode, >>> not a poorly defined precision value" in the discussion[1], >>> as he and Richi suggested, the existing macros >>> {FLOAT,{,LONG_}DOUBLE}_TYPE_SIZE will be replaced with a >>> hook mode_for_floating_type. To be prepared for that, this >>> patch is to replace use of LONG_DOUBLE_TYPE_SIZE in d with >>> TYPE_PRECISION of long_double_type_node. >>> >>> [1] https://gcc.gnu.org/pipermail/gcc-patches/2024-May/651209.html >>> >> >> Thanks, one question though: Is TYPE_PRECISION really equivalent to >> LONG_DOUBLE_TYPE_SIZE? > > Yes, it's guaranteed by the code in build_common_tree_nodes: > > long_double_type_node = make_node (REAL_TYPE); > TYPE_PRECISION (long_double_type_node) = LONG_DOUBLE_TYPE_SIZE; > layout_type (long_double_type_node); > > , the macro LONG_DOUBLE_TYPE_SIZE is assigned to TYPE_PRECISION of > long_double_type_node, layout_type will only pick up one mode as > the given precision and won't change it. > >> >> Unless LONG_DOUBLE_TYPE_SIZE was poorly named to begin with, I'd assume >> the answer to be "no". > > I'm afraid it's poorly named before. >
Thanks for confirming Kewen. I suspect then that this code is incorrectly using this macro, and it should instead be using: int_size_in_bytes(long_double_type_node) as any padding should be considered as part of the overall type size for the purpose that this field serves in the D part of the front-end. Are you able to update the patch this way instead? Otherwise I'm happy to push the change instead. Thanks again, Iain.