The following fixes dependence handling in GRAPHITE which currently
cannot cope with DRs that may alias but are not compatible so to be
handled solely by looking at their DR_ACCESS_FNs. This includes
pointer vs. array accesses for example.
Bootstrapped and tested on x86_64-unknown-linux-gnu, approved by
Sebastian in the PR, applied to trunk.
Richard.
PS: we may eventually do better in build_alias_set by using
full dependence analysis rather than only dr_may_alias_p to
get at the recently added cases disambiguating component arrays.
PPS: I checked tramp3d now works but I don't have a self-contained
testcase, so no testcase.
2017-09-15 Richard Biener <rguent...@suse.de>
PR tree-optimization/68823
* graphite-scop-detection.c (build_alias_set): If we have a
possible dependence check whether we can handle them by just
looking at the DRs DR_ACCESS_FNs.
(build_scops): If build_alias_set fails, fail the SCOP.
Index: gcc/graphite-scop-detection.c
===================================================================
--- gcc/graphite-scop-detection.c (revision 252756)
+++ gcc/graphite-scop-detection.c (working copy)
@@ -1855,7 +1857,7 @@ try_generate_gimple_bb (scop_p scop, bas
/* Compute alias-sets for all data references in DRS. */
-static void
+static bool
build_alias_set (scop_p scop)
{
int num_vertices = scop->drs.length ();
@@ -1868,6 +1870,18 @@ build_alias_set (scop_p scop)
for (j = i+1; scop->drs.iterate (j, &dr2); j++)
if (dr_may_alias_p (dr1->dr, dr2->dr, true))
{
+ /* Dependences in the same alias set need to be handled
+ by just looking at DR_ACCESS_FNs. */
+ if (DR_NUM_DIMENSIONS (dr1->dr) != DR_NUM_DIMENSIONS (dr2->dr)
+ || ! operand_equal_p (DR_BASE_OBJECT (dr1->dr),
+ DR_BASE_OBJECT (dr2->dr),
+ OEP_ADDRESS_OF)
+ || ! types_compatible_p (TREE_TYPE (DR_BASE_OBJECT (dr1->dr)),
+ TREE_TYPE (DR_BASE_OBJECT (dr2->dr))))
+ {
+ free_graph (g);
+ return false;
+ }
add_edge (g, i, j);
add_edge (g, j, i);
}
@@ -1883,6 +1897,7 @@ build_alias_set (scop_p scop)
scop->drs[i].alias_set = g->vertices[i].component + 1;
free_graph (g);
+ return true;
}
/* Gather BBs and conditions for a SCOP. */
@@ -2075,7 +2090,12 @@ build_scops (vec<scop_p> *scops)
scop->pbbs.qsort (cmp_pbbs);
order.release ();
- build_alias_set (scop);
+ if (! build_alias_set (scop))
+ {
+ DEBUG_PRINT (dp << "[scop-detection-fail] cannot handle
dependences\n");
+ free_scop (scop);
+ continue;
+ }
/* Do not optimize a scop containing only PBBs that do not belong
to any loops. */
