[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 Richard Biener changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED --- Comment #14 from Richard Biener --- Fixed.
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 --- Comment #13 from CVS Commits --- The master branch has been updated by Richard Biener : https://gcc.gnu.org/g:31ec413098bd334115aff73fc755e49afd3ac371 commit r14-3076-g31ec413098bd334115aff73fc755e49afd3ac371 Author: Richard Biener Date: Tue Aug 8 12:46:42 2023 +0200 tree-optimization/110924 - fix vop liveness for noreturn const CFG parts The virtual operand live problem used by sinking assumes we have virtual uses at each end point of the CFG but as shown in the PR this isn't true for parts for example ending in __builtin_unreachable. The following removes the optimization made possible by this and now requires marking backedges. PR tree-optimization/110924 * tree-ssa-live.h (virtual_operand_live): Update comment. * tree-ssa-live.cc (virtual_operand_live::get_live_in): Remove optimization, look at each predecessor. * tree-ssa-sink.cc (pass_sink_code::execute): Mark backedges. * gcc.dg/torture/pr110924.c: New testcase.
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 --- Comment #12 from Richard Biener --- (In reply to Richard Biener from comment #11) > Variant (1) is just the following, but I'm unsure as to the possible effects > of that ... (test coverage will be very low anyway) > > diff --git a/gcc/tree-ssa-operands.cc b//gcc/tree-ssa-operands.cc > index 57e393ae164..c8ac98b4e06 100644 > --- a/gcc/tree-ssa-operands.cc > +++ b/gcc/tree-ssa-operands.cc > @@ -696,7 +696,8 @@ operands_scanner::maybe_add_call_vops (gcall *stmt) >/* A 'pure' or a 'const' function never call-clobbers anything. */ >if (!(call_flags & (ECF_PURE | ECF_CONST))) > add_virtual_operand (opf_def); > - else if (!(call_flags & ECF_CONST)) > + else if (!(call_flags & ECF_CONST) > + || (call_flags & ECF_NORETURN)) > add_virtual_operand (opf_use); > } > } That ICEs for example tree-ssa/cunroll-4.c because that inserts __builtin_unreachable () calls and this function is explicitly marked const noreturn (if you use that combo manually you get a diagnostic). The ICE is because cunroll doesn't add virtual operands or updates SSA. But it also shows that sinking into __builtin_unreachable () ending regions will have the same issue and the ipa pure-const/modref fix won't fix that. I'm going to try fixing the live problem :/
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 --- Comment #11 from Richard Biener --- Variant (1) is just the following, but I'm unsure as to the possible effects of that ... (test coverage will be very low anyway) diff --git a/gcc/tree-ssa-operands.cc b/gcc/tree-ssa-operands.cc index 57e393ae164..c8ac98b4e06 100644 --- a/gcc/tree-ssa-operands.cc +++ b/gcc/tree-ssa-operands.cc @@ -696,7 +696,8 @@ operands_scanner::maybe_add_call_vops (gcall *stmt) /* A 'pure' or a 'const' function never call-clobbers anything. */ if (!(call_flags & (ECF_PURE | ECF_CONST))) add_virtual_operand (opf_def); - else if (!(call_flags & ECF_CONST)) + else if (!(call_flags & ECF_CONST) + || (call_flags & ECF_NORETURN)) add_virtual_operand (opf_use); } }
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 --- Comment #10 from Richard Biener --- Created attachment 55705 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55705=edit prototype This implements option two - Honza, I think the pure-const hunk is sound but I didn't find a proper "lattice" for modref so had to modify the pure/const setting places (three, ugh) - is there a better way to tell modref the "base" lattice value is pure and not const?
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924
Richard Biener changed:
What|Removed |Added
CC||hubicka at gcc dot gnu.org
--- Comment #9 from Richard Biener ---
Hm, OK. So I actually thought of this issue. It's basically a hole in the
requirement of all function "exits" having a virtual use and thus virtual
PHIs being created along the paths to it. I was aware of GIMPLE_RESX and
thought about const noreturn (but that attribute combination is rejected).
IPA pure-const detects func_15 as looping 'const' and noreturn:
Function is locally const.
Function found to be noreturn: func_15
Function found to be looping const: func_15/2
Declaration updated to be looping const: func_15/2
so there's two ways to "fix" this, one - drop the assumption we have
PHIs on the paths to function exit (including in not returning regions).
That makes
virtual_operand_live::get_live_in (basic_block bb)
{
...
/* Since we don't have a virtual PHI we can now pick any of the
incoming edges liveout value. All returns from the function have
a virtual use forcing generation of virtual PHIs. */
edge_iterator ei;
edge e;
FOR_EACH_EDGE (e, ei, bb->preds)
if (liveout[e->src->index])
{
if (EDGE_PRED (bb, 0) != e)
liveout[EDGE_PRED (bb, 0)->src->index] = liveout[e->src->index];
return liveout[e->src->index];
}
instead required to check each edge and we can't simply take the value
from the immediate dominator as fallback. When we discover divergence
we need to return NULL (unknown - nobody created the actually live VOP).
The other alternative is to make sure we _do_ have the virtual operand.
Either by making sure the "invalid" combination of const + noreturn
isn't detected or by creating a virtual use in that case anyway
(and fixup code because of that inconsistency).
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 Richard Biener changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org --- Comment #8 from Richard Biener --- I will have a look.
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 David Binderman changed: What|Removed |Added CC||rguenth at gcc dot gnu.org --- Comment #7 from David Binderman --- (In reply to Andrew Pinski from comment #4) > Confirmed. > > I am 99% sure it was r14-2946-g46c8c225455273 Perhaps it would be worthwhile to ask Richard to have a look.
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924
--- Comment #6 from David Binderman ---
Reduced C code is
func_4_p_7, func_4_l_3204;
func_15() __attribute__((cold));
func_15() {
for (;;)
;
}
func_15_alias() __attribute__((alias("func_15")));
func_4() {
func_15_alias(func_4_p_7 && safe_sub_func_uint64_t_u_u(), func_4_l_3204);
}
-O1 is enough to show the bug.
cvise $ /home/dcb38/gcc/results/bin/gcc -c -w -O1 bug946.c
bug946.c: In function ‘func_4’:
bug946.c:8:1: error: stmt with wrong VUSE
8 | func_4() {
| ^~
# VUSE <.MEM_5(D)>
func_4_l_3204.0_1 = func_4_l_3204;
expected .MEM_6
during GIMPLE pass: sink
bug946.c:8:1: internal compiler error: verify_ssa failed
0x10c63cb verify_ssa(bool, bool)
../../trunk.year/gcc/tree-ssa.cc:1203
0xd2ccdf execute_function_todo(function*, void*)
../../trunk.year/gcc/passes.cc:2095
0xd2b6c1 execute_todo(unsigned int)
../../trunk.year/gcc/passes.cc:2142
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 Andrew Pinski changed: What|Removed |Added CC||shaohua.li at inf dot ethz.ch --- Comment #5 from Andrew Pinski --- *** Bug 110929 has been marked as a duplicate of this bug. ***
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 Andrew Pinski changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2023-08-07 Ever confirmed|0 |1 --- Comment #4 from Andrew Pinski --- Confirmed. I am 99% sure it was r14-2946-g46c8c225455273
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 David Binderman changed: What|Removed |Added CC||dcb314 at hotmail dot com --- Comment #3 from David Binderman --- I see this one also. It first goes wrong between g:0460c1221627938b and g:4a0633d4d499cf97, some 38 commits.
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924 --- Comment #2 from Andrew Pinski --- Confirmed, though this is undefined code unless a is always 0.
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924
--- Comment #1 from Andrew Pinski ---
Here is a testcase without calling main:
```
int a[1], b, c, d, e, f, g;
[[gnu::noinline]]
void h(int i, int j) {
int *k = 0;
if (*k)
h(0, 0);
g = i && d;
}
int jj() {
if (c)
goto l;
if (!a)
while (1) {
f = 1;
while (f)
h(b && jj(), e);
while (1)
;
l:;
}
return 0;
}
```
[Bug tree-optimization/110924] [14 Regression] ICE on valid code at -O{s,2,3} on x86_64-linux-gnu: verify_ssa failed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110924
Andrew Pinski changed:
What|Removed |Added
Keywords||ice-on-valid-code
Target Milestone|--- |14.0
Summary|ICE on valid code at|[14 Regression] ICE on
|-O{s,2,3} on|valid code at -O{s,2,3} on
|x86_64-linux-gnu: |x86_64-linux-gnu:
|verify_ssa failed |verify_ssa failed
Version|unknown |14.0
