2011-12-07 Roman Zhuykov <zhroma@ispras.ru>
* ddg.c: New VEC.
(add_cross_iteration_register_deps): Store information about
clobbers before first write to a register. Use collected
information to create anti-dependencies from last uses.
---
@@ -49,6 +49,10 @@ along with GCC; see the file COPYING3. If not see
/* A flag indicating that a ddg edge belongs to an SCC or not. */
enum edge_flag {NOT_IN_SCC = 0, IN_SCC};
+/* A vector of dependencies needed while processing clobbers. */
+DEF_VEC_P(df_ref);
+DEF_VEC_ALLOC_P(df_ref,heap);
+
/* Forward declarations. */
static void add_backarc_to_ddg (ddg_ptr, ddg_edge_ptr);
static void add_backarc_to_scc (ddg_scc_ptr, ddg_edge_ptr);
@@ -273,24 +277,52 @@ create_ddg_dep_no_link (ddg_ptr g, ddg_node_ptr from, ddg_node_ptr to,
static void
add_cross_iteration_register_deps (ddg_ptr g, df_ref last_def)
{
- int regno = DF_REF_REGNO (last_def);
+ unsigned int regno = DF_REF_REGNO (last_def);
struct df_link *r_use;
int has_use_in_bb_p = false;
- rtx def_insn = DF_REF_INSN (last_def);
+ rtx insn, def_insn = DF_REF_INSN (last_def);
ddg_node_ptr last_def_node = get_node_of_insn (g, def_insn);
ddg_node_ptr use_node;
#ifdef ENABLE_CHECKING
struct df_rd_bb_info *bb_info = DF_RD_BB_INFO (g->bb);
#endif
- df_ref first_def = df_bb_regno_first_def_find (g->bb, regno);
+ static VEC(df_ref,heap) *clobbers;
+ df_ref first_write_def = NULL;
+ df_ref *def_rec;
+ unsigned int uid;
+
+ clobbers = VEC_alloc (df_ref, heap, 0);
+
+ FOR_BB_INSNS (g->bb, insn)
+ {
+ if (!INSN_P (insn))
+ continue;
+ uid = INSN_UID (insn);
+ for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+ {
+ df_ref def = *def_rec;
+ if (DF_REF_REGNO (def) == regno)
+ {
+ VEC_safe_push (df_ref, heap, clobbers, def);
+ if (!(DF_REF_FLAGS (def)
+ & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))
+ {
+ first_write_def = def;
+ break;
+ }
+ }
+ }
+ if (first_write_def != NULL)
+ break;
+ }
gcc_assert (last_def_node);
- gcc_assert (first_def);
+ gcc_assert (first_write_def);
#ifdef ENABLE_CHECKING
- if (DF_REF_ID (last_def) != DF_REF_ID (first_def))
+ if (DF_REF_ID (last_def) != DF_REF_ID (first_write_def))
gcc_assert (!bitmap_bit_p (&bb_info->gen,
- DF_REF_ID (first_def)));
+ DF_REF_ID (first_write_def)));
#endif
/* Create inter-loop true dependences and anti dependences. */
@@ -316,29 +348,35 @@ add_cross_iteration_register_deps (ddg_ptr g, df_ref last_def)
}
else if (!DEBUG_INSN_P (use_insn))
{
+ unsigned int i;
+ df_ref curr_def;
/* Add anti deps from last_def's uses in the current iteration
- to the first def in the next iteration. We do not add ANTI
- dep when there is an intra-loop TRUE dep in the opposite
- direction, but use regmoves to fix such disregarded ANTI
- deps when broken. If the first_def reaches the USE then
- there is such a dep. */
- ddg_node_ptr first_def_node = get_node_of_insn (g,
- DF_REF_INSN (first_def));
-
- gcc_assert (first_def_node);
-
- /* Always create the edge if the use node is a branch in
- order to prevent the creation of reg-moves.
- If the address that is being auto-inc or auto-dec in LAST_DEF
- is used in USE_INSN then do not remove the edge to make sure
- reg-moves will not be created for that address. */
- if (DF_REF_ID (last_def) != DF_REF_ID (first_def)
- || !flag_modulo_sched_allow_regmoves
- || JUMP_P (use_node->insn)
- || autoinc_var_is_used_p (DF_REF_INSN (last_def), use_insn))
- create_ddg_dep_no_link (g, use_node, first_def_node, ANTI_DEP,
- REG_DEP, 1);
-
+ to the first def and all clobbers before it in the next iteration.
+ We do not add ANTI dep when there is an intra-loop TRUE dep
+ in the opposite direction, but use regmoves to fix such
+ disregarded ANTI deps when broken. If the curr_def reaches
+ the USE then there is such a dep. */
+ FOR_EACH_VEC_ELT (df_ref, clobbers, i, curr_def)
+ {
+ if (DF_REF_ID (last_def) != DF_REF_ID (curr_def)
+ /* Some hard regs (for ex. CC-flags) can't be renamed.
+ || HARD_REGISTER_P (DF_REF_REG (last_def)) */
+ || !flag_modulo_sched_allow_regmoves
+ /* If the address that is being auto-inc or auto-dec in LAST_DEF
+ is used in USE_INSN then do not remove the edge to make sure
+ reg-moves will not be created for that address. */
+ || autoinc_var_is_used_p (DF_REF_INSN (last_def), use_insn)
+ /* Always create the edge if the use node is a branch in
+ order to prevent the creation of reg-moves. */
+ || JUMP_P (use_node->insn))
+ {
+ ddg_node_ptr curr_def_node = get_node_of_insn (g,
+ DF_REF_INSN (curr_def));
+ gcc_assert (curr_def_node);
+ create_ddg_dep_no_link (g, use_node, curr_def_node,
+ ANTI_DEP, REG_DEP, 1);
+ }
+ }
}
}
/* Create an inter-loop output dependence between LAST_DEF (which is the
@@ -352,14 +390,16 @@ add_cross_iteration_register_deps (ddg_ptr g, df_ref last_def)
{
ddg_node_ptr dest_node;
- if (DF_REF_ID (last_def) == DF_REF_ID (first_def))
+ if (DF_REF_ID (last_def) == DF_REF_ID (first_write_def))
return;
- dest_node = get_node_of_insn (g, DF_REF_INSN (first_def));
+ dest_node = get_node_of_insn (g, DF_REF_INSN (first_write_def));
gcc_assert (dest_node);
create_ddg_dep_no_link (g, last_def_node, dest_node,
OUTPUT_DEP, REG_DEP, 1);
}
+
+ VEC_free (df_ref, heap, clobbers);
}
/* Build inter-loop dependencies, by looking at DF analysis backwards. */
static void