[1/3,RFC] fsra: Add final gimple sra just before expander
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Commit Message
This patch adds a new mode for sra pass: "fsra".
This 'fsra' pass handle function parameters and returns as candidates.
And run it at the end of GIMPLE passes sequences.
gcc/ChangeLog:
* passes.def: Add pass pass_sra_final.
* tree-pass.h (make_pass_sra_final): Declare make_pass_sra_final.
* tree-sra.cc (enum sra_mode): New enum item SRA_MODE_FINAL_INTRA.
(build_accesses_from_assign): Accept SRA_MODE_FINAL_INTRA.
(find_var_candidates): Collect candidates for SRA_MODE_FINAL_INTRA.
(final_intra_sra): New function.
(class pass_sra_final): New pass class.
(make_pass_sra_final): New function.
---
gcc/passes.def | 2 ++
gcc/tree-pass.h | 1 +
gcc/tree-sra.cc | 81 +++++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 78 insertions(+), 6 deletions(-)
@@ -449,6 +449,8 @@ along with GCC; see the file COPYING3. If not see
NEXT_PASS (pass_harden_conditional_branches);
NEXT_PASS (pass_harden_compares);
NEXT_PASS (pass_warn_access, /*early=*/false);
+ NEXT_PASS (pass_sra_final);
+
NEXT_PASS (pass_cleanup_cfg_post_optimizing);
NEXT_PASS (pass_warn_function_noreturn);
@@ -366,6 +366,7 @@ extern gimple_opt_pass *make_pass_early_tree_profile (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_cleanup_eh (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_sra (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_sra_early (gcc::context *ctxt);
+extern gimple_opt_pass *make_pass_sra_final (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_tail_recursion (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_tail_calls (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_fix_loops (gcc::context *ctxt);
@@ -21,14 +21,16 @@ along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
/* This file implements Scalar Reduction of Aggregates (SRA). SRA is run
- twice, once in the early stages of compilation (early SRA) and once in the
- late stages (late SRA). The aim of both is to turn references to scalar
- parts of aggregates into uses of independent scalar variables.
+ three times, once in the early stages of compilation (early SRA) and once
+ in the late stages (late SRA). The aim of them is to turn references to
+ scalar parts of aggregates into uses of independent scalar variables.
- The two passes are nearly identical, the only difference is that early SRA
+ The three passes are nearly identical, the difference are that early SRA
does not scalarize unions which are used as the result in a GIMPLE_RETURN
statement because together with inlining this can lead to weird type
- conversions.
+ conversions. The third pass is more care about parameters and returns,
+ it would be helpful for the parameters and returns which are passed through
+ registers.
Both passes operate in four stages:
@@ -104,6 +106,7 @@ along with GCC; see the file COPYING3. If not see
/* Enumeration of all aggregate reductions we can do. */
enum sra_mode { SRA_MODE_EARLY_IPA, /* early call regularization */
SRA_MODE_EARLY_INTRA, /* early intraprocedural SRA */
+ SRA_MODE_FINAL_INTRA, /* final gimple intraprocedural SRA */
SRA_MODE_INTRA }; /* late intraprocedural SRA */
/* Global variable describing which aggregate reduction we are performing at
@@ -1437,7 +1440,8 @@ build_accesses_from_assign (gimple *stmt)
}
if (lacc && racc
- && (sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA)
+ && (sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA
+ || sra_mode == SRA_MODE_FINAL_INTRA)
&& !lacc->grp_unscalarizable_region
&& !racc->grp_unscalarizable_region
&& AGGREGATE_TYPE_P (TREE_TYPE (lhs))
@@ -2149,6 +2153,24 @@ find_var_candidates (void)
parm = DECL_CHAIN (parm))
ret |= maybe_add_sra_candidate (parm);
+ /* fsra only care about parameters and returns */
+ if (sra_mode == SRA_MODE_FINAL_INTRA)
+ {
+ if (!DECL_RESULT (current_function_decl))
+ return ret;
+
+ edge_iterator ei;
+ edge e;
+ FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)
+ if (greturn *r = safe_dyn_cast<greturn *> (*gsi_last_bb (e->src)))
+ {
+ tree val = gimple_return_retval (r);
+ if (val && VAR_P (val))
+ ret |= maybe_add_sra_candidate (val);
+ }
+ return ret;
+ }
+
FOR_EACH_LOCAL_DECL (cfun, i, var)
{
if (!VAR_P (var))
@@ -5017,6 +5039,14 @@ late_intra_sra (void)
return perform_intra_sra ();
}
+/* Perform "final sra" intraprocedural SRA just before expander. */
+static unsigned int
+final_intra_sra (void)
+{
+ sra_mode = SRA_MODE_FINAL_INTRA;
+ return perform_intra_sra ();
+}
+
static bool
gate_intra_sra (void)
@@ -5099,3 +5129,42 @@ make_pass_sra (gcc::context *ctxt)
{
return new pass_sra (ctxt);
}
+
+namespace
+{
+const pass_data pass_data_sra_final = {
+ GIMPLE_PASS, /* type */
+ "fsra", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_TREE_SRA, /* tv_id */
+ (PROP_cfg | PROP_ssa), /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_update_ssa, /* todo_flags_finish */
+};
+
+class pass_sra_final : public gimple_opt_pass
+{
+public:
+ pass_sra_final (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_sra_final, ctxt)
+ {
+ }
+
+ /* opt_pass methods: */
+ bool gate (function *) final override { return gate_intra_sra (); }
+ unsigned int execute (function *) final override
+ {
+ return final_intra_sra ();
+ }
+
+}; // class pass_sra_final
+
+} // namespace
+
+gimple_opt_pass *
+make_pass_sra_final (gcc::context *ctxt)
+{
+ return new pass_sra_final (ctxt);
+}