[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 --- Comment #9 from CVS Commits --- The master branch has been updated by Jakub Jelinek : https://gcc.gnu.org/g:eedda4e160856b7ac0c533ac9445161d0fd88660 commit r11-7033-geedda4e160856b7ac0c533ac9445161d0fd88660 Author: Jakub Jelinek Date: Tue Feb 2 10:01:40 2021 +0100 testsuite: Add testcase for already fixed PR [PR97960] This testcase has been fixed by r11-5904-g4cf70c20cb10acd6fb1016611d05540728176b60 so I'm checking it in so that we can close the PR. 2021-02-02 Jakub Jelinek PR tree-optimization/97960 * g++.dg/torture/pr97960.C: New test.
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 --- Comment #8 from Jakub Jelinek --- Indeed, r11-5904-g4cf70c20cb10acd6fb1016611d05540728176b60 fixed it. I'll add the testcase into the testsuite after testing it.
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 --- Comment #7 from Alex Coplan --- FWIW, the testcase now exits cleanly on AArch64 with current trunk.
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 --- Comment #6 from Richard Biener --- Is it maybe fixed with the latest re-org of split_constant_offset?
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org --- Comment #5 from Jakub Jelinek --- Richard, did you have time to look into this yet?
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 rsandifo at gcc dot gnu.org changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |rsandifo at gcc dot gnu.org --- Comment #4 from rsandifo at gcc dot gnu.org --- Mine. Might not be able to get to it for a few days though.
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960
--- Comment #3 from Richard Biener ---
Creating dr for b[_7]
base_address: &b
offset from base address: (ssizetype) ((sizetype) (signed char) _5 * 4)
constant offset from base address: -1012
step: 4
base alignment: 32
base misalignment: 0
offset alignment: 4
step alignment: 4
base_object: b
Access function 0: {(int) h_20, +, 1}_2
looks like the wrong sign for the constant offset.
#0 split_constant_offset_1 (type=,
op0=, code=NOP_EXPR, op1=,
var=0x7fffba10, off=0x7fffba08, cache=..., limit=0x7fffc19c)
now, var_min/max is UNSIGNED -3 / -1 (precision 8), woff is 3
we compute -3 + 3 == 0 and overflow to true (UNSIGNED arithmetic)
_5 = (unsigned char) _35;
_6 = _5 + 3;
h_20 = (signed char) _6;
but then we continue with
/* Calculate (ssizetype) OP0 - (ssizetype) TMP_VAR. */
widest_int diff = (widest_int::from (op0_min, sgn)
- widest_int::from (var_min, sgn));
getting -253. I remember this place has changed quite some times and
wide (sign-extended) vs. widest (signed) ints do not make it easier
to see what's correct ...
I'm defering to Richard here. The C testcase trips at this point just
twice (ldist and vectorizer) so it's easy enough to 'catch' in a debugger.
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 Richard Biener changed: What|Removed |Added Priority|P1 |P2 CC||rguenth at gcc dot gnu.org
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960 Martin Liška changed: What|Removed |Added Status|UNCONFIRMED |NEW CC||marxin at gcc dot gnu.org, ||rsandifo at gcc dot gnu.org Last reconfirmed||2020-11-23 Priority|P3 |P1 Ever confirmed|0 |1 Target Milestone|--- |8.5 Keywords||wrong-code --- Comment #2 from Martin Liška --- Confirmed!
[Bug tree-optimization/97960] [8/9/10/11 Regression] Wrong code at -O3 since r8-6511-g3ae129323d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97960
--- Comment #1 from Alex Coplan ---
C testcase:
const int *c(const int *p, const int *q)
{
if (*p < *q)
return q;
return p;
}
short a[575];
unsigned b[25];
unsigned char g;
int main()
{
for (int e = 0; e < 23; ++e)
a[e * 23] = 16137;
int t1 = g;
int t2 = 253;
signed char h = *c(&t1, &t2) + 3;
for (; h < 24; h++)
b[h] = 1064739102;
for (int e = 0; e < 23; ++e)
if (a[e * 23] != 16137)
__builtin_abort();
}
