[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 Tamar Christina changed: What|Removed |Added Resolution|--- |FIXED Status|ASSIGNED|RESOLVED --- Comment #9 from Tamar Christina --- Fixed. Thanks for the report and let me know if there's something still broken.
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 --- Comment #8 from GCC Commits --- The master branch has been updated by Tamar Christina : https://gcc.gnu.org/g:e79c5855ab39d96baa7c6bec63eb97715abcf68d commit r14-7197-ge79c5855ab39d96baa7c6bec63eb97715abcf68d Author: Tamar Christina Date: Fri Jan 12 15:26:29 2024 + middle-end: fill in reduction PHI for all alt exits [PR113178] When we have a loop with more than 2 exits and a reduction I forgot to fill in the PHI value for all alternate exits. All alternate exits use the same PHI value so we should loop over the new PHI elements and copy the value across since we call the reduction calculation code only once for all exits. This was normally covered up by earlier parts of the compiler rejecting loops incorrectly (which has been fixed now). Note that while I can use the loop in all cases, the reason I separated out the main and alt exit is so that if you pass the wrong edge the macro will assert. gcc/ChangeLog: PR tree-optimization/113178 * tree-vect-loop.cc (vect_create_epilog_for_reduction): Fill in all alternate exits. gcc/testsuite/ChangeLog: PR tree-optimization/113178 * gcc.dg/vect/vect-early-break_101-pr113178.c: New test. * gcc.dg/vect/vect-early-break_102-pr113178.c: New test.
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 --- Comment #7 from GCC Commits --- The master branch has been updated by Tamar Christina : https://gcc.gnu.org/g:411de96dbf2bdafc7a90ebbfc63e68afd6388d29 commit r14-7195-g411de96dbf2bdafc7a90ebbfc63e68afd6388d29 Author: Tamar Christina Date: Fri Jan 12 15:25:34 2024 + middle-end: maintain LCSSA form when peeled vector iterations have virtual operands This patch fixes several interconnected issues. 1. When picking an exit we wanted to check for niter_desc.may_be_zero not true. i.e. we want to pick an exit which we know will iterate at least once. However niter_desc.may_be_zero is not a boolean. It is a tree that encodes a boolean value. !niter_desc.may_be_zero is just checking if we have some information, not what the information is. This leads us to pick a more difficult to vectorize exit more often than we should. 2. Because we had this bug, we used to pick an alternative exit much more ofthen which showed one issue, when the loop accesses memory and we "invert it" we would corrupt the VUSE chain. This is because on an peeled vector iteration every exit restarts the loop (i.e. they're all early) BUT since we may have performed a store, the vUSE would need to be updated. This version maintains virtual PHIs correctly in these cases. Note that we can't simply remove all of them and recreate them because we need the PHI nodes still in the right order for if skip_vector. 3. Since we're moving the stores to a safe location I don't think we actually need to analyze whether the store is in range of the memref, because if we ever get there, we know that the loads must be in range, and if the loads are in range and we get to the store we know the early breaks were not taken and so the scalar loop would have done the VF stores too. 4. Instead of searching for where to move stores to, they should always be in exit belonging to the latch. We can only ever delay stores and even if we pick a different exit than the latch one as the main one, effects still happen in program order when vectorized. If we don't move the stores to the latch exit but instead to whever we pick as the "main" exit then we can perform incorrect memory accesses (luckily these are trapped by verify_ssa). 5. We only used to analyze loads inside the same BB as an early break, and also we'd never analyze the ones inside the block where we'd be moving memory references to. This is obviously bogus and to fix it this patch splits apart the two constraints. We first validate that all load memory references are in bounds and only after that do we perform the alias checks for the writes. This makes the code simpler to understand and more trivially correct. gcc/ChangeLog: PR tree-optimization/113137 PR tree-optimization/113136 PR tree-optimization/113172 PR tree-optimization/113178 * tree-vect-loop-manip.cc (slpeel_tree_duplicate_loop_to_edge_cfg): Maintain PHIs on inverted loops. (vect_do_peeling): Maintain virtual PHIs on inverted loops. * tree-vect-loop.cc (vec_init_loop_exit_info): Pick exit closes to latch. (vect_create_loop_vinfo): Record all conds instead of only alt ones. gcc/testsuite/ChangeLog: PR tree-optimization/113137 PR tree-optimization/113136 PR tree-optimization/113172 PR tree-optimization/113178 * g++.dg/vect/vect-early-break_4-pr113137.cc: New test. * g++.dg/vect/vect-early-break_5-pr113137.cc: New test. * gcc.dg/vect/vect-early-break_95-pr113137.c: New test. * gcc.dg/vect/vect-early-break_96-pr113136.c: New test. * gcc.dg/vect/vect-early-break_97-pr113172.c: New test.
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 Martin Jambor changed: What|Removed |Added Keywords|needs-bisection | --- Comment #6 from Martin Jambor --- (In reply to David Binderman from comment #4) > Reduced range seems to be g:0994ddd86f9c3d82 to g:a657c7e3518fcfc7. > > All commits in this range are by Tamar. Specifically r14-6822-g01f4251b8775c8 (Tamar Christina: middle-end: Support vectorization of loops with multiple exits.)
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 Richard Biener changed: What|Removed |Added Priority|P3 |P1
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 Tamar Christina changed: What|Removed |Added Status|NEW |ASSIGNED See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=113137 Assignee|unassigned at gcc dot gnu.org |tnfchris at gcc dot gnu.org CC||tnfchris at gcc dot gnu.org --- Comment #5 from Tamar Christina --- Thanks, fixed by submitted patch for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113137
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 David Binderman changed: What|Removed |Added CC||tamar.christina at arm dot com --- Comment #4 from David Binderman --- Reduced range seems to be g:0994ddd86f9c3d82 to g:a657c7e3518fcfc7. All commits in this range are by Tamar.
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 --- Comment #3 from David Binderman --- After some bisection, range seems to be g:2902300340928989 to g:ed60b2868abdb793, a range of 21 commits.
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 --- Comment #2 from David Binderman --- The bug first seems to occur sometime between git:514ea1df444ca7f6 and git:f19ceb2d49afdfa5, a distance of 83 commits.
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178
Andrew Pinski changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Keywords||needs-bisection
Ever confirmed|0 |1
Last reconfirmed||2023-12-30
--- Comment #1 from Andrew Pinski ---
More reduced testcase and converted into one is C code too:
```
struct PixelWeight {
int m_SrcStart;
int m_Weights[16];
};
char h;
void f(struct PixelWeight *pPixelWeights) {
int dest_g_m;
long tt;
for (int j = 0; j < 16; j++) {
int *p = 0;
if (j < pPixelWeights->m_SrcStart)
p = tt ? >m_Weights[0] : 0;
int pWeight = *p;
dest_g_m += pWeight;
}
h = dest_g_m;
}
```
[Bug tree-optimization/113178] [14 Regression] ice in find_uses_to_rename_use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113178 Andrew Pinski changed: What|Removed |Added CC||pinskia at gcc dot gnu.org Target||x86_64-linux-gnu Target Milestone|--- |14.0 Summary|ice in |[14 Regression] ice in |find_uses_to_rename_use |find_uses_to_rename_use Keywords||ice-on-valid-code Component|c++ |tree-optimization
