[PATCH] Reload global options when strict aliasing is dropped (PR ipa/79043).

[Martin Liška <mliska at suse dot cz>]

As mentioned in the PR, we currently do not properly reload global
optimization options when we drop strict-aliasing flag on a function
that equals to cfun.

Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.

Ready to be installed?
Martin

>From 53108a01c5fcb6fcfca15b389e76217b724915c3 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Tue, 10 Jan 2017 14:43:04 +0100
Subject: [PATCH] Reload global options when strict aliasing is dropped (PR
 ipa/79043).

gcc/ChangeLog:

2017-01-10  Martin Liska  <mliska@suse.cz>

	PR ipa/79043
	* function.c (set_cfun): Add new argument force.
	* function.h (set_cfun): Likewise.
	* ipa-inline-transform.c (inline_call): Use the function when
	strict alising from is dropped for function we inline to.

gcc/testsuite/ChangeLog:

2017-01-10  Martin Liska  <mliska@suse.cz>

	PR ipa/79043
	* gcc.c-torture/execute/pr79043.c: New test.
---
 gcc/function.c                                |  4 ++--
 gcc/function.h                                |  2 +-
 gcc/ipa-inline-transform.c                    |  8 ++++++++
 gcc/testsuite/gcc.c-torture/execute/pr79043.c | 21 +++++++++++++++++++++
 4 files changed, 32 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr79043.c

diff --git a/gcc/function.c b/gcc/function.c
index 7fde96adbe3..f625489205b 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -4811,9 +4811,9 @@ invoke_set_current_function_hook (tree fndecl)
 /* cfun should never be set directly; use this function.  */
 
 void
-set_cfun (struct function *new_cfun)
+set_cfun (struct function *new_cfun, bool force)
 {
-  if (cfun != new_cfun)
+  if (cfun != new_cfun || force)
     {
       cfun = new_cfun;
       invoke_set_current_function_hook (new_cfun ? new_cfun->decl : NULL_TREE);
diff --git a/gcc/function.h b/gcc/function.h
index fb3cbbc3346..fb8f57ae385 100644
--- a/gcc/function.h
+++ b/gcc/function.h
@@ -613,7 +613,7 @@ extern tree block_chainon (tree, tree);
 extern void number_blocks (tree);
 
 /* cfun shouldn't be set directly; use one of these functions instead.  */
-extern void set_cfun (struct function *new_cfun);
+extern void set_cfun (struct function *new_cfun, bool force = false);
 extern void push_cfun (struct function *new_cfun);
 extern void pop_cfun (void);
 
diff --git a/gcc/ipa-inline-transform.c b/gcc/ipa-inline-transform.c
index 7725fadd6d8..a8e73cd6967 100644
--- a/gcc/ipa-inline-transform.c
+++ b/gcc/ipa-inline-transform.c
@@ -340,6 +340,8 @@ inline_call (struct cgraph_edge *e, bool update_original,
   if (DECL_FUNCTION_PERSONALITY (callee->decl))
     DECL_FUNCTION_PERSONALITY (to->decl)
       = DECL_FUNCTION_PERSONALITY (callee->decl);
+
+  bool reload_optimization_node = false;
   if (!opt_for_fn (callee->decl, flag_strict_aliasing)
       && opt_for_fn (to->decl, flag_strict_aliasing))
     {
@@ -352,6 +354,7 @@ inline_call (struct cgraph_edge *e, bool update_original,
 		 to->name (), to->order);
       DECL_FUNCTION_SPECIFIC_OPTIMIZATION (to->decl)
 	 = build_optimization_node (&opts);
+      reload_optimization_node = true;
     }
 
   inline_summary *caller_info = inline_summaries->get (to);
@@ -412,9 +415,14 @@ inline_call (struct cgraph_edge *e, bool update_original,
 		     callee->name (), callee->order, to->name (), to->order);
 	  DECL_FUNCTION_SPECIFIC_OPTIMIZATION (to->decl)
 	     = build_optimization_node (&opts);
+	  reload_optimization_node = true;
 	}
     }
 
+  /* Reload global optimization flags.  */
+  if (reload_optimization_node && DECL_STRUCT_FUNCTION (to->decl) == cfun)
+    set_cfun (cfun, true);
+
   /* If aliases are involved, redirect edge to the actual destination and
      possibly remove the aliases.  */
   if (e->callee != callee)
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr79043.c b/gcc/testsuite/gcc.c-torture/execute/pr79043.c
new file mode 100644
index 00000000000..b7fcc8260dc
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr79043.c
@@ -0,0 +1,21 @@
+/* PR ipa/78791 */
+
+int val;
+
+int *ptr = &val;
+float *ptr2 = &val;
+
+static
+__attribute__((always_inline, optimize ("-fno-strict-aliasing")))
+typepun ()
+{
+  *ptr2=0;
+}
+
+main()
+{
+  *ptr=1;
+  typepun ();
+  if (*ptr)
+    __builtin_abort ();
+}
-- 
2.11.0