mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-05 20:01:28 +08:00
Code Issues Packages Projects Releases Wiki Activity

tree-ssa-alias.c (maybe_create_global_var): Don't just return if .GLOBAL_VAR has been created.

Browse Source 
* tree-ssa-alias.c (maybe_create_global_var): Don't just
	return if .GLOBAL_VAR has been created.

From-SVN: r85268
This commit is contained in:
Diego Novillo 2004-07-28 17:57:27 +00:00 committed by Diego Novillo
parent 852c7b12c5
commit e0d3bb46f1
2 changed files with 25 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
gcc/ChangeLog
View File

@ -1,3 +1,8 @@
2004-07-28 Diego Novillo <dnovillo@redhat.com>
* tree-ssa-alias.c (maybe_create_global_var): Don't just
return if .GLOBAL_VAR has been created.
2004-07-28 Diego Novillo <dnovillo@redhat.com>
* tree-ssa.c (verify_flow_insensitive_alias_info): Process

39
gcc/tree-ssa-alias.c
View File

@ -1492,33 +1492,34 @@ maybe_create_global_var (struct alias_info *ai)
size_t i, n_clobbered;
/* No need to create it, if we have one already. */
if (global_var)
return;
if (global_var == NULL_TREE)
{
/* Count all the call-clobbered variables. */
n_clobbered = 0;
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, n_clobbered++);
/* Count all the call-clobbered variables. */
n_clobbered = 0;
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, n_clobbered++);
/* Create .GLOBAL_VAR if we have too many call-clobbered
variables. We also create .GLOBAL_VAR when there no
call-clobbered variables to prevent code motion
transformations from re-arranging function calls that may
have side effects. For instance,
/* Create .GLOBAL_VAR if we have too many call-clobbered variables.
We also create .GLOBAL_VAR when there no call-clobbered variables
to prevent code motion transformations from re-arranging function
calls that may have side effects. For instance,
foo ()
foo ()
{
int a = f ();
g ();
h (a);
}
There are no call-clobbered variables in foo(), so it would be
entirely possible for a pass to want to move the call to f()
after the call to g(). If f() has side effects, that would be
wrong. Creating .GLOBAL_VAR in this case will insert VDEFs for
it and prevent such transformations. */
if (n_clobbered == 0
|| ai->num_calls_found * n_clobbered >= (size_t) GLOBAL_VAR_THRESHOLD)
create_global_var ();
There are no call-clobbered variables in foo(), so it would
be entirely possible for a pass to want to move the call to
f() after the call to g(). If f() has side effects, that
would be wrong. Creating .GLOBAL_VAR in this case will
insert VDEFs for it and prevent such transformations. */
if (n_clobbered == 0
|| ai->num_calls_found * n_clobbered >= (size_t) GLOBAL_VAR_THRESHOLD)
create_global_var ();
}
/* If the function has calls to clobbering functions and .GLOBAL_VAR has
been created, make it an alias for all call-clobbered variables. */