[tree-sra] Fix to set up correct context for call to compute_inline_parameter (PR44768)

Submitted by Ramana Radhakrishnan on July 7, 2010, 11:10 a.m.

Details

Message ID 1278501026.25686.23.camel@e102325-lin.cambridge.arm.com
State New
Headers show

Commit Message

Ramana Radhakrishnan July 7, 2010, 11:10 a.m.
On Wed, 2010-07-07 at 11:33 +0200, Richard Guenther wrote:

> Switching cfun is expensive.  Why and where does
> compute_inline_parameters end up using cfun?  We should fix
> that instead.

The reason compute_inline_parameters ends up using cfun /
current_function_decl is because this ends up calling
estimated_stack_frame_size that ends up calling a backend hook that uses
current_function_decl as can be seen in the audit trail
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44768#c5

Based on your idea after our IRC chat - Does this look any better ?
Verified that this actually generates the correct code by manual
inspection of generated code. Ok after bootstrapping on
arm-linux-gnueabi and regression testing ?

cheers
Ramana

2010-07-07  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

	PR bootstrap/44768
	* cfgexpand.c (estimated_stack_frame_size): Make self-contained
	with respect to current_function_decl. Pass decl of the function.
	* tree-inline.h (estimated_stack_frame_size): Adjust prototype.
	* ipa-inline.c (compute_inline_parameters): Pass decl to
	estimated_stack_frame_size.

Comments

Richard Guenther July 7, 2010, 11:14 a.m.
On Wed, Jul 7, 2010 at 1:10 PM, Ramana Radhakrishnan
<ramana.radhakrishnan@arm.com> wrote:
>
> On Wed, 2010-07-07 at 11:33 +0200, Richard Guenther wrote:
>
>> Switching cfun is expensive.  Why and where does
>> compute_inline_parameters end up using cfun?  We should fix
>> that instead.
>
> The reason compute_inline_parameters ends up using cfun /
> current_function_decl is because this ends up calling
> estimated_stack_frame_size that ends up calling a backend hook that uses
> current_function_decl as can be seen in the audit trail
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44768#c5
>
> Based on your idea after our IRC chat - Does this look any better ?
> Verified that this actually generates the correct code by manual
> inspection of generated code. Ok after bootstrapping on
> arm-linux-gnueabi and regression testing ?

Yes.

Thanks,
RIchard.

> cheers
> Ramana
>
> 2010-07-07  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
>
>        PR bootstrap/44768
>        * cfgexpand.c (estimated_stack_frame_size): Make self-contained
>        with respect to current_function_decl. Pass decl of the function.
>        * tree-inline.h (estimated_stack_frame_size): Adjust prototype.
>        * ipa-inline.c (compute_inline_parameters): Pass decl to
>        estimated_stack_frame_size.
>
>
>

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Index: ipa-inline.c
===================================================================
--- ipa-inline.c	(revision 161901)
+++ ipa-inline.c	(working copy)
@@ -2019,7 +2019,7 @@  compute_inline_parameters (struct cgraph
 
   /* Estimate the stack size for the function.  But not at -O0
      because estimated_stack_frame_size is a quadratic problem.  */
-  self_stack_size = optimize ? estimated_stack_frame_size () : 0;
+  self_stack_size = optimize ? estimated_stack_frame_size (node->decl) : 0;
   inline_summary (node)->estimated_self_stack_size = self_stack_size;
   node->global.estimated_stack_size = self_stack_size;
   node->global.stack_frame_offset = 0;
Index: cfgexpand.c
===================================================================
--- cfgexpand.c	(revision 161901)
+++ cfgexpand.c	(working copy)
@@ -1252,8 +1252,8 @@  fini_vars_expansion (void)
   stack_vars_alloc = stack_vars_num = 0;
 }
 
-/* Make a fair guess for the size of the stack frame of the current
-   function.  This doesn't have to be exact, the result is only used
+/* Make a fair guess for the size of the stack frame of the decl
+   passed.  This doesn't have to be exact, the result is only used
    in the inline heuristics.  So we don't want to run the full stack
    var packing algorithm (which is quadratic in the number of stack
    vars).  Instead, we calculate the total size of all stack vars.
@@ -1261,12 +1261,15 @@  fini_vars_expansion (void)
    vars doesn't happen very often.  */
 
 HOST_WIDE_INT
-estimated_stack_frame_size (void)
+estimated_stack_frame_size (tree decl)
 {
   HOST_WIDE_INT size = 0;
   size_t i;
   tree var, outer_block = DECL_INITIAL (current_function_decl);
   unsigned ix;
+  tree old_cur_fun_decl = current_function_decl;
+  current_function_decl = decl;
+  push_cfun (DECL_STRUCT_FUNCTION (decl));
 
   init_vars_expansion ();
 
@@ -1287,7 +1290,8 @@  estimated_stack_frame_size (void)
       size += account_stack_vars ();
       fini_vars_expansion ();
     }
-
+  pop_cfun ();
+  current_function_decl = old_cur_fun_decl;
   return size;
 }
 
Index: tree-inline.h
===================================================================
--- tree-inline.h	(revision 161901)
+++ tree-inline.h	(working copy)
@@ -185,6 +185,6 @@  extern tree remap_decl (tree decl, copy_
 extern tree remap_type (tree type, copy_body_data *id);
 extern gimple_seq copy_gimple_seq_and_replace_locals (gimple_seq seq);
 
-extern HOST_WIDE_INT estimated_stack_frame_size (void);
+extern HOST_WIDE_INT estimated_stack_frame_size (tree);
 
 #endif /* GCC_TREE_INLINE_H */