On Tue, 1 Jul 2025, Jakub Jelinek wrote: > On Tue, Jul 01, 2025 at 10:43:09AM +0200, Richard Biener wrote: > > > The following patch fixes that by > > > 1) moving the musttail pass 2 passes earlier (this is mostly just > > > for -O0/-Og, for normal optimization levels musttail calls are > > > handled in the tailc pass), i.e. across the sanopt and cleanup_eh > > > passes > > > > didn't we have other cases where cleanup_eh was required for musttail > > to work? So I think we want to have that before musttail? We should > > be able to swap sanopt and eh_cleanup? > > I think we've discussed we want to try for GCC 16 cleanup_eh somewhere in > the -O1+ optimization pass set, in between IPA and tailc (and I'll try to do > that at some point during stage1). > > I've actually tried > --- gcc/passes.def 2025-06-30 22:16:11.258688529 +0200 > +++ gcc/passes.def 2025-07-01 10:47:37.020634803 +0200 > @@ -444,9 +444,9 @@ along with GCC; see the file COPYING3. > NEXT_PASS (pass_lower_switch_O0); > NEXT_PASS (pass_asan_O0); > NEXT_PASS (pass_tsan_O0); > - NEXT_PASS (pass_sanopt); > NEXT_PASS (pass_cleanup_eh); > NEXT_PASS (pass_musttail); > + NEXT_PASS (pass_sanopt); > NEXT_PASS (pass_lower_resx); > NEXT_PASS (pass_nrv); > NEXT_PASS (pass_gimple_isel); > together with the non-empty_eh_cleanup tree-tailcall.cc changes from the > patch, but that resulted in the following ICE: > /home/jakub/src/gcc/gcc/testsuite/gcc.dg/asan/pr106190.c: In function 'main': > /home/jakub/src/gcc/gcc/testsuite/gcc.dg/asan/pr106190.c:6:1: internal > compiler error: in expand_builtin_eh_common, at except.cc:2097 > 0x2dc62cf internal_error(char const*, ...) > ../../gcc/diagnostic-global-context.cc:517 > 0xeaeced fancy_abort(char const*, int, char const*) > ../../gcc/diagnostic.cc:1810 > 0x81940a expand_builtin_eh_common > ../../gcc/except.cc:2097 > 0x11ad909 expand_builtin_eh_pointer(tree_node*) > ../../gcc/except.cc:2108 > 0x11deac2 expand_expr_real_1(tree_node*, rtx_def*, machine_mode, > expand_modifier, rtx_def**, bool) > ../../gcc/expr.cc:12535 > 0x11ecddd store_expr(tree_node*, rtx_def*, int, bool, bool) > ../../gcc/expr.cc:6762 > 0x11efb28 expand_assignment(tree_node*, tree_node*, bool) > ../../gcc/expr.cc:6483 > 0x11efb28 expand_assignment(tree_node*, tree_node*, bool) > ../../gcc/expr.cc:5971 > 0x1093629 expand_call_stmt > ../../gcc/cfgexpand.cc:3202 > 0x1093629 expand_gimple_stmt_1 > ../../gcc/cfgexpand.cc:4276 > 0x1093629 expand_gimple_stmt > ../../gcc/cfgexpand.cc:4423 > 0x1095617 expand_gimple_basic_block > ../../gcc/cfgexpand.cc:6539 > 0x1097a07 execute > ../../gcc/cfgexpand.cc:7286 > > Given that empty_eh_cleanup handles already almost everything, just > didn't know how to handle the resx to internal step which was quite > trivial, I thought it will be easier not to reorder cleanup_eh pass, > especially for 15.2 backport and when I have no idea what went wrong > in the pr106190 testcase (the ICE is about not finding some region).
I see. Fine with me then. It's a bit of a whack-a-mole with musttail, esp. wrt sanitizers ... Richard.
