Fix alignment for local variable [PR90811]

 - The alignment for local variable was adjust during estimate_stack_frame_size,
   however it seems wrong spot to adjust that, expand phase will adjust that
   but it little too late to some gimple optimization, which rely on certain
   target hooks need to check alignment, forwprop is an example for
   that, result of simplify_builtin_call rely on the alignment on some
   target like ARM or RISC-V.

 - Exclude static local var and hard register var in the process of
   alignment adjustment.

 - This patch fix gfortran.dg/pr45636.f90 for arm and riscv.

 - Regression test on riscv32/riscv64 and x86_64-linux-gnu, no new fail
   introduced.

gcc/ChangeLog

	PR target/90811
	* Makefile.in (OBJS): Add adjust-alignment.o.
	* adjust-alignment.c (pass_data_adjust_alignment): New.
	(pass_adjust_alignment): New.
	(pass_adjust_alignment::execute): New.
	(make_pass_adjust_alignment): New.
	* tree-pass.h (make_pass_adjust_alignment): New.
	* passes.def: Add pass_adjust_alignment.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9eee988e12cd4bf7e36afdb2bb6f132c43df2766..fdaa94ae8b94ae84aebf3f36ea087c9d49a2c487 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2020-05-20  Kito Cheng  <kito.cheng@sifive.com>
+
+       PR target/90811
+       * Makefile.in (OBJS): Add adjust-alignment.o.
+       * adjust-alignment.c (pass_data_adjust_alignment): New.
+       (pass_adjust_alignment): New.
+       (pass_adjust_alignment::execute): New.
+       (make_pass_adjust_alignment): New.
+       * tree-pass.h (make_pass_adjust_alignment): New.
+       * passes.def: Add pass_adjust_alignment.
+
 2020-05-19  Alex Coplan  <alex.coplan@arm.com>
 
        PR target/94591

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 9ba21f735f6dfe632f57a18a0a9216ce6dac50a4..0fe2ba241e398cb6d7346d329f6196cdde9932ad 100644 (file)
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1267,6 +1267,7 @@ OBJS = \
        insn-recog.o \
        insn-enums.o \
        ggc-page.o \
+       adjust-alignment.o \
        alias.o \
        alloc-pool.o \
        auto-inc-dec.o \

diff --git a/gcc/adjust-alignment.c b/gcc/adjust-alignment.c
new file mode 100644 (file)
index 0000000..40cfd18
--- /dev/null
+++ b/gcc/adjust-alignment.c
@@ -0,0 +1,84 @@
+/* Adjust alignment for local variable.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   Contributed by Kito Cheng <kito.cheng@sifive.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "backend.h"
+#include "target.h"
+#include "tree.h"
+#include "tree-pass.h"
+#include "tm_p.h"
+
+namespace {
+
+const pass_data pass_data_adjust_alignment =
+{
+  GIMPLE_PASS, /* type */
+  "adjust_alignment", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  TV_NONE, /* tv_id */
+  0, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  0, /* todo_flags_finish */
+};
+
+class pass_adjust_alignment : public gimple_opt_pass
+{
+public:
+  pass_adjust_alignment (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_adjust_alignment, ctxt)
+  {}
+
+  virtual unsigned int execute (function *);
+}; // class pass_adjust_alignment
+
+} // anon namespace
+
+/* Entry point to adjust_alignment pass.  */
+unsigned int
+pass_adjust_alignment::execute (function *fun)
+{
+  size_t i;
+  tree var;
+
+  FOR_EACH_LOCAL_DECL (fun, i, var)
+    {
+      /* Don't adjust aligment for static local var and hard register var.  */
+      if (is_global_var (var) || DECL_HARD_REGISTER (var))
+       continue;
+
+      unsigned align = LOCAL_DECL_ALIGNMENT (var);
+
+      /* Make sure alignment only increase.  */
+      gcc_assert (align >= DECL_ALIGN (var));
+
+      SET_DECL_ALIGN (var, align);
+    }
+  return 0;
+}
+
+gimple_opt_pass *
+make_pass_adjust_alignment (gcc::context *ctxt)
+{
+  return new pass_adjust_alignment (ctxt);
+}

diff --git a/gcc/passes.def b/gcc/passes.def
index 2bf2cb78fc50b64ca2fc01d226960a95987787f9..92cbe587a8a5bb080c9c3bb4bcd67d55d3ea6c6f 100644 (file)
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -183,6 +183,7 @@ along with GCC; see the file COPYING3.  If not see
   NEXT_PASS (pass_oacc_device_lower);
   NEXT_PASS (pass_omp_device_lower);
   NEXT_PASS (pass_omp_target_link);
+  NEXT_PASS (pass_adjust_alignment);
   NEXT_PASS (pass_all_optimizations);
   PUSH_INSERT_PASSES_WITHIN (pass_all_optimizations)
       NEXT_PASS (pass_remove_cgraph_callee_edges);

diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index a1207a20a3c9e84eee8035281b518e616ba57cfc..576b3f674340087ee7a236846ad835458b8b2091 100644 (file)
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -480,6 +480,7 @@ extern gimple_opt_pass *make_pass_sprintf_length (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_walloca (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_coroutine_lower_builtins (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_coroutine_early_expand_ifns (gcc::context *ctxt);
+extern gimple_opt_pass *make_pass_adjust_alignment (gcc::context *ctxt);
 
 /* IPA Passes */
 extern simple_ipa_opt_pass *make_pass_ipa_lower_emutls (gcc::context *ctxt);