https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87188
--- Comment #24 from rguenther at suse dot de <rguenther at suse dot de> --- On Wed, 12 Sep 2018, dave.anglin at bell dot net wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87188 > > --- Comment #23 from dave.anglin at bell dot net --- > On 2018-09-12 4:03 AM, rguenth at gcc dot gnu.org wrote: > > --- Comment #22 from Richard Biener <rguenth at gcc dot gnu.org> --- > > (In reply to dave.anglin from comment #21) > >> On 2018-09-09 2:46 PM, rguenther at suse dot de wrote: > >>> In the last patch you replace arg0 || arg1 with arg0 & & arg1, that looks > >>> wrong. Otherwise the patch looks OK. > >> It was intentional. See the comment in dojump.c: > >> > >> /* If function pointers need to be "canonicalized" before they can > >> be reliably compared, then canonicalize them. > >> Only do this if*both* sides of the comparison are function > >> pointers. > >> If one side isn't, we want a noncanonicalized comparison. See PR > >> middle-end/17564. */ > >> if (targetm.have_canonicalize_funcptr_for_compare () > >> && POINTER_TYPE_P (TREE_TYPE (treeop0)) > >> && POINTER_TYPE_P (TREE_TYPE (treeop1)) > >> && FUNC_OR_METHOD_TYPE_P (TREE_TYPE (TREE_TYPE (treeop0))) > >> && FUNC_OR_METHOD_TYPE_P (TREE_TYPE (TREE_TYPE (treeop1)))) > >> > >> Based on this, I thought that we could allow do_store_flag to output a > >> "scc" instruction > >> when both sides weren't function or method pointers. > > Ah, I see. > Based on my testing, when we have a function or method pointer for one > of the operands, the other > operand is either a function, method or void pointer. An implicit cast > occurs if one compares a function > pointer to say an int or int*. Of course, a warning is generated in > that case. So, we want to canonicalize > when one of the operands is a function or method pointer. This > canonicalizes comparisons of a function > pointer and a void pointer. > > Attached is latest patch. LGTM.
