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* [Bug middle-end/112087] New: gimple front end: Simple testcase with array fails to round trip
@ 2023-10-25 14:08 acoplan at gcc dot gnu.org
2023-10-27 12:57 ` [Bug middle-end/112087] " rguenth at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: acoplan at gcc dot gnu.org @ 2023-10-25 14:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112087
Bug ID: 112087
Summary: gimple front end: Simple testcase with array fails to
round trip
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: acoplan at gcc dot gnu.org
Target Milestone: ---
Reproducer:
$ cat t.c
long f()
{
int a[4];
return (long)a;
}
$ gcc/xgcc -B gcc -c t.c -S -o /dev/null -O2 -fdump-tree-ssa-gimple=gimple.c
$ cat gimple.c
long int __GIMPLE (ssa)
f ()
{
int a[4];
long int _1;
__BB(2):
_1 = (long int) _Literal (int[4] *)&a;
a ={v} _Literal (int[4]) {CLOBBER(eol)};
return _1;
}
$ gcc/xgcc -B gcc -c gimple.c -S -o /dev/null -O2 -fgimple
gimple.c: In function ‘f’:
gimple.c:8:35: error: expected ‘)’ before ‘*’ token
8 | _1 = (long int) _Literal (int[4] *)&a;
| ^~
| )
gimple.c:9:6: error: expected expression before ‘{’ token
9 | a ={v} _Literal (int[4]) {CLOBBER(eol)};
| ^
gimple.c:12:1: error: invalid types in nop conversion
12 | }
| ^
long int
int[4]
_1 = (long int) &a;
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug middle-end/112087] gimple front end: Simple testcase with array fails to round trip
2023-10-25 14:08 [Bug middle-end/112087] New: gimple front end: Simple testcase with array fails to round trip acoplan at gcc dot gnu.org
@ 2023-10-27 12:57 ` rguenth at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-10-27 12:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112087
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2023-10-27
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
"Round-tripping" in the sense of
gcc -fdump-tree-X-gimple=- t.c -S | gcc -x c -fgimple -
was never the intention.
Yes, parsing of CLOBBERs isn't implemented, nor is parsing of
"gimple_has_volatile_ops", but since that's redundant info recomputed
at update_stmt time we can just scrap it at dump time (but then it's
a bit odd to not see it with -gimple ..).
It would be nice to have bugreports more specific that "cannot round-trip A or
B".
Two bugs for this.
Parsing of ={v}
Parsing of {CLOBBER} (and variants)
parsing of ={v} is a bit difficult since it would need to be tentative
(there's always a reason why seemingly "easy" things are not yet done).
Finding a better syntax for dumping the flags on a stmt might help.
Workaround for both: use -fstack-reuse=none
^ permalink raw reply [flat|nested] 2+ messages in thread
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2023-10-25 14:08 [Bug middle-end/112087] New: gimple front end: Simple testcase with array fails to round trip acoplan at gcc dot gnu.org
2023-10-27 12:57 ` [Bug middle-end/112087] " rguenth at gcc dot gnu.org
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