Hi! PR83391/PR83396 failed because debug bind stmts were put before labels. Alex said that is undesirable, and that right now we want to allow just debug begin stmt markers before or intermixed with labels.
This patch ensures that through verification, which is what defines what is and isn't valid GIMPLE. If we ever reconsider it, either allow further stmts or disallow even debug begin stmt markers, we can easily also tweak the verifier. The patch has been successfully bootstrapped/regtested as part of the: https://gcc.gnu.org/ml/gcc-patches/2017-12/msg00811.html https://gcc.gnu.org/ml/gcc-patches/2017-12/msg00808.html https://gcc.gnu.org/bugzilla/attachment.cgi?id=42861 https://gcc.gnu.org/bugzilla/attachment.cgi?id=42866 https://gcc.gnu.org/ml/gcc-patches/2017-12/msg00794.html patchset, without the msg00811.html patch it of course doesn't survive bootstrap, as we insert debug bind stmts before labels in those cases. Ok for trunk once the msg00811.html patch or something similar is committed? 2017-12-13 Jakub Jelinek <ja...@redhat.com> * tree-cfg.c (verify_gimple_in_cfg): Verify no non-label stmts with the exception of debug begin stmt markers appear before labels. --- gcc/tree-cfg.c.jj 2017-12-12 21:24:23.000000000 +0100 +++ gcc/tree-cfg.c 2017-12-13 07:44:15.622790922 +0100 @@ -5380,6 +5380,7 @@ verify_gimple_in_cfg (struct function *f err |= err2; } + bool label_allowed = true; for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple *stmt = gsi_stmt (gsi); @@ -5396,6 +5397,19 @@ verify_gimple_in_cfg (struct function *f err2 = true; } + /* Labels may be preceded only by debug markers, not debug bind + or source bind or any other statements. */ + if (gimple_code (stmt) == GIMPLE_LABEL) + { + if (!label_allowed) + { + error ("gimple label in the middle of a basic block"); + err2 = true; + } + } + else if (!gimple_debug_begin_stmt_p (stmt)) + label_allowed = false; + err2 |= verify_gimple_stmt (stmt); err2 |= verify_location (&blocks, gimple_location (stmt)); Jakub
