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* [Bug middle-end/106870] New: ctrl_altering flag is not set correctly
@ 2022-09-07 11:28 rguenth at gcc dot gnu.org
2022-09-07 13:32 ` [Bug middle-end/106870] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-09-07 11:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106870
Bug ID: 106870
Summary: ctrl_altering flag is not set correctly
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
When trying to add the following verification I run into various issues with
the gimple_ctrl_altering_p flag which stmt_ends_bb_p which sets found_ctrl_stmt
ultimatively relies on for the noreturn case.
diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index bbe08357d6e..a939a11d8bb 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -5708,6 +5709,14 @@ gimple_verify_flow_info (void)
seen_nondebug_stmt = true;
}
+ if (!found_ctrl_stmt && EDGE_COUNT (bb->succs) != 1)
+ {
+ error ("basic block %d has no control altering stmt but %d "
+ "outgoing edges",
+ bb->index, EDGE_COUNT (bb->succs));
+ err = 1;
+ }
+
gsi = gsi_last_nondebug_bb (bb);
if (gsi_end_p (gsi))
continue;
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/106870] ctrl_altering flag is not set correctly
2022-09-07 11:28 [Bug middle-end/106870] New: ctrl_altering flag is not set correctly rguenth at gcc dot gnu.org
@ 2022-09-07 13:32 ` rguenth at gcc dot gnu.org
2022-09-08 14:06 ` cvs-commit at gcc dot gnu.org
2022-09-08 14:08 ` rguenth at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-09-07 13:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106870
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
gcc.dg/torture/pr57036-2.c shows how inlining and non-local gotos come into
play here.
Note the flag was specifically invented to not make CFG verification ICE
when a function in the middle of a block becomes noreturn, for example
via IPA analysis. It wasn't necessarily required to have the flag set
on stmts ending a BB.
Still not having the flag set prevents nothing to put stmts after such
call and we'd not complain.
gcc.dg/torture/pr83055.c shows how the checking is confused as called from
gimple_flow_call_edges_add after adding loads of fake edges.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/106870] ctrl_altering flag is not set correctly
2022-09-07 11:28 [Bug middle-end/106870] New: ctrl_altering flag is not set correctly rguenth at gcc dot gnu.org
2022-09-07 13:32 ` [Bug middle-end/106870] " rguenth at gcc dot gnu.org
@ 2022-09-08 14:06 ` cvs-commit at gcc dot gnu.org
2022-09-08 14:08 ` rguenth at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-09-08 14:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106870
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:
https://gcc.gnu.org/g:78ef801b7263606d27a6a752a40cbeecc584fb3d
commit r13-2541-g78ef801b7263606d27a6a752a40cbeecc584fb3d
Author: Richard Biener <rguenther@suse.de>
Date: Wed Sep 7 12:01:34 2022 +0200
Fix some gimple_ctrl_altering_p mistakes
CFG cleanup resets the control altering flag for noreturn functions
when they are ECF_LEAF (like __builtin_unreachable ()). The
.ABNORMAL_DISPATCHER call built during CFG construction is not
marked as control altering. Several passes inserting traps or
unreachables fail to set the flag. And more.
PR middle-end/106870
* gimple-harden-conditionals.cc (insert_check_and_trap):
Set the control-altering flag on the built IFN_TRAP.
* gimple.cc (gimple_build_builtin_unreachable): Likewise.
* tree-cfg.cc (handle_abnormal_edges): Set the control-altering
flag on the .ABNORMAL_DISPATCHER call.
* tree-cfgcleanup.cc (cleanup_call_ctrl_altering_flag): Avoid
resetting the control altering flag for ECF_NORETURN calls.
(cleanup_control_flow_bb): Set the control altering flag on
discovered noreturn calls.
* symtab-thunks.cc (expand_thunk): Set the control altering
flag for the noreturn tailcall case.
* tree-eh.cc (lower_resx): Likewisw for trap and unwind_resume
calls.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/106870] ctrl_altering flag is not set correctly
2022-09-07 11:28 [Bug middle-end/106870] New: ctrl_altering flag is not set correctly rguenth at gcc dot gnu.org
2022-09-07 13:32 ` [Bug middle-end/106870] " rguenth at gcc dot gnu.org
2022-09-08 14:06 ` cvs-commit at gcc dot gnu.org
@ 2022-09-08 14:08 ` rguenth at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-09-08 14:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106870
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
This fixes some cases but leaves others not fixed.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-09-08 14:08 UTC | newest]
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2022-09-07 11:28 [Bug middle-end/106870] New: ctrl_altering flag is not set correctly rguenth at gcc dot gnu.org
2022-09-07 13:32 ` [Bug middle-end/106870] " rguenth at gcc dot gnu.org
2022-09-08 14:06 ` cvs-commit at gcc dot gnu.org
2022-09-08 14:08 ` rguenth at gcc dot gnu.org
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