diff options
| -rw-r--r-- | gcc/ChangeLog | 11 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/pr39612.c | 21 | ||||
| -rw-r--r-- | gcc/tree-ssa-loop-im.c | 47 |
4 files changed, 76 insertions, 8 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 42c4af7..61d5ce5 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,14 @@ +2020-05-04 Richard Biener <rguenther@suse.de> + + PR tree-optimization/39612 + * tree-ssa-loop-im.c (im_mem_ref::loaded): New member. + (set_ref_loaded_in_loop): New. + (mark_ref_loaded): Likewise. + (gather_mem_refs_stmt): Call mark_ref_loaded for loads. + (execute_sm): Avoid issueing a load when it was not there. + (execute_sm_if_changed): Avoid issueing warnings for the + conditional store. + 2020-05-04 Martin Jambor <mjambor@suse.cz> PR ipa/93385 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index bbdd51a..341b674 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-05-04 Richard Biener <rguenther@suse.de> + + PR tree-optimization/39612 + * gcc.dg/tree-ssa/pr39612.c: New testcase. + 2020-05-04 Uroš Bizjak <ubizjak@gmail.com> PR target/94650 diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr39612.c b/gcc/testsuite/gcc.dg/tree-ssa/pr39612.c new file mode 100644 index 0000000..884f905 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr39612.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-lim2-details -Wuninitialized" } */ + +void foo(int *); +void f2(int dst[3], int R) +{ + int i, inter[2]; + + for (i = 1; i < R; i++) { + if (i & 8) + { + inter[0] = 1; + inter[1] = 1; + } + } + + foo(inter); +} + +/* { dg-final { scan-tree-dump-times "Executing store motion" 2 "lim2" } } */ +/* { dg-final { scan-tree-dump-not " = inter\\\[\[0-1\]\\\];" "lim2" } } */ diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c index abd5f70..18e5c18 100644 --- a/gcc/tree-ssa-loop-im.c +++ b/gcc/tree-ssa-loop-im.c @@ -127,6 +127,8 @@ public: bitmap stored; /* The set of loops in that this memory location is stored to. */ + bitmap loaded; /* The set of loops in that this memory location + is loaded from. */ vec<mem_ref_loc> accesses_in_loop; /* The locations of the accesses. Vector indexed by the loop number. */ @@ -1395,6 +1397,7 @@ mem_ref_alloc (ao_ref *mem, unsigned hash, unsigned id) ref->ref_decomposed = false; ref->hash = hash; ref->stored = NULL; + ref->loaded = NULL; bitmap_initialize (&ref->indep_loop, &lim_bitmap_obstack); bitmap_initialize (&ref->dep_loop, &lim_bitmap_obstack); ref->accesses_in_loop.create (1); @@ -1435,6 +1438,27 @@ mark_ref_stored (im_mem_ref *ref, class loop *loop) loop = loop_outer (loop); } +/* Set the LOOP bit in REF loaded bitmap and allocate that if + necessary. Return whether a bit was changed. */ + +static bool +set_ref_loaded_in_loop (im_mem_ref *ref, class loop *loop) +{ + if (!ref->loaded) + ref->loaded = BITMAP_ALLOC (&lim_bitmap_obstack); + return bitmap_set_bit (ref->loaded, loop->num); +} + +/* Marks reference REF as loaded in LOOP. */ + +static void +mark_ref_loaded (im_mem_ref *ref, class loop *loop) +{ + while (loop != current_loops->tree_root + && set_ref_loaded_in_loop (ref, loop)) + loop = loop_outer (loop); +} + /* Gathers memory references in statement STMT in LOOP, storing the information about them in the memory_accesses structure. Marks the vops accessed through unrecognized statements there as @@ -1571,6 +1595,8 @@ gather_mem_refs_stmt (class loop *loop, gimple *stmt) bitmap_set_bit (&memory_accesses.refs_stored_in_loop[loop->num], ref->id); mark_ref_stored (ref, loop); } + else + mark_ref_loaded (ref, loop); init_lim_data (stmt)->ref = ref->id; return; } @@ -1968,6 +1994,8 @@ execute_sm_if_changed (edge ex, tree mem, tree tmp_var, tree flag, gsi = gsi_start_bb (then_bb); /* Insert actual store. */ stmt = gimple_build_assign (unshare_expr (mem), tmp_var); + /* Make sure to not warn about maybe-uninit uses of tmp_var here. */ + gimple_set_no_warning (stmt, true); gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING); edge e1 = single_succ_edge (new_bb); @@ -2115,14 +2143,17 @@ execute_sm (class loop *loop, vec<edge> exits, im_mem_ref *ref) by move_computations after all dependencies. */ gsi = gsi_for_stmt (first_mem_ref_loc (loop, ref)->stmt); - /* FIXME/TODO: For the multi-threaded variant, we could avoid this - load altogether, since the store is predicated by a flag. We - could, do the load only if it was originally in the loop. */ - load = gimple_build_assign (tmp_var, unshare_expr (ref->mem.ref)); - lim_data = init_lim_data (load); - lim_data->max_loop = loop; - lim_data->tgt_loop = loop; - gsi_insert_before (&gsi, load, GSI_SAME_STMT); + /* Avoid doing a load if there was no load of the ref in the loop. + Esp. when the ref is not always stored we cannot optimize it + away later. */ + if (ref->loaded && bitmap_bit_p (ref->loaded, loop->num)) + { + load = gimple_build_assign (tmp_var, unshare_expr (ref->mem.ref)); + lim_data = init_lim_data (load); + lim_data->max_loop = loop; + lim_data->tgt_loop = loop; + gsi_insert_before (&gsi, load, GSI_SAME_STMT); + } if (multi_threaded_model_p) { |