https://gcc.gnu.org/g:05ef04d644c1a460b3af266a7766001c93fe1a6a
commit r15-9780-g05ef04d644c1a460b3af266a7766001c93fe1a6a
Author: Richard Biener <rguent...@suse.de>
Date: Tue Apr 29 15:08:52 2025 +0200
tree-optimization/119960 - add validity checking to SLP scheduling
The following adds checks that when we search for a vector stmt
insert location we arrive at one where all required operand defs
are dominating the insert location. At the moment any such
failure only blows up during SSA verification.
There's the long-standing issue that we do not verify there
exists a valid schedule of the SLP graph from BB vectorization
into the existing CFG. We do not have the ability to insert
vector stmts on the dominance frontier "end", nor to insert
LC PHIs that would be eventually required.
This should be done all differently, computing the schedule
during analysis and failing if we can't schedule.
PR tree-optimization/119960
* tree-vect-slp.cc (vect_schedule_slp_node): Sanity
check dominance check on operand defs.
(cherry picked from commit 5f44fcdfe18e72f2900d2757375843e88d32c535)
Diff:
---
gcc/tree-vect-slp.cc | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 958f000e7d6d..ed432a95d33f 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -11162,9 +11162,14 @@ vect_schedule_slp_node (vec_info *vinfo,
== cycle_phi_info_type);
gphi *phi = as_a <gphi *>
(vect_find_last_scalar_stmt_in_slp (child)->stmt);
- if (!last_stmt
- || vect_stmt_dominates_stmt_p (last_stmt, phi))
+ if (!last_stmt)
last_stmt = phi;
+ else if (vect_stmt_dominates_stmt_p (last_stmt, phi))
+ last_stmt = phi;
+ else if (vect_stmt_dominates_stmt_p (phi, last_stmt))
+ ;
+ else
+ gcc_unreachable ();
}
/* We are emitting all vectorized stmts in the same place and
the last one is the last.
@@ -11175,9 +11180,14 @@ vect_schedule_slp_node (vec_info *vinfo,
FOR_EACH_VEC_ELT (SLP_TREE_VEC_DEFS (child), j, vdef)
{
gimple *vstmt = SSA_NAME_DEF_STMT (vdef);
- if (!last_stmt
- || vect_stmt_dominates_stmt_p (last_stmt, vstmt))
+ if (!last_stmt)
+ last_stmt = vstmt;
+ else if (vect_stmt_dominates_stmt_p (last_stmt, vstmt))
last_stmt = vstmt;
+ else if (vect_stmt_dominates_stmt_p (vstmt, last_stmt))
+ ;
+ else
+ gcc_unreachable ();
}
}
else if (!SLP_TREE_VECTYPE (child))
@@ -11190,9 +11200,14 @@ vect_schedule_slp_node (vec_info *vinfo,
&& !SSA_NAME_IS_DEFAULT_DEF (def))
{
gimple *stmt = SSA_NAME_DEF_STMT (def);
- if (!last_stmt
- || vect_stmt_dominates_stmt_p (last_stmt, stmt))
+ if (!last_stmt)
+ last_stmt = stmt;
+ else if (vect_stmt_dominates_stmt_p (last_stmt, stmt))
last_stmt = stmt;
+ else if (vect_stmt_dominates_stmt_p (stmt, last_stmt))
+ ;
+ else
+ gcc_unreachable ();
}
}
else
@@ -11213,9 +11228,14 @@ vect_schedule_slp_node (vec_info *vinfo,
&& !SSA_NAME_IS_DEFAULT_DEF (vdef))
{
gimple *vstmt = SSA_NAME_DEF_STMT (vdef);
- if (!last_stmt
- || vect_stmt_dominates_stmt_p (last_stmt, vstmt))
+ if (!last_stmt)
+ last_stmt = vstmt;
+ else if (vect_stmt_dominates_stmt_p (last_stmt, vstmt))
last_stmt = vstmt;
+ else if (vect_stmt_dominates_stmt_p (vstmt, last_stmt))
+ ;
+ else
+ gcc_unreachable ();
}
}
}
