On Wed, May 21, 2014 at 3:16 PM, Martin Jambor <mjam...@suse.cz> wrote:
> Hi,
>
> this demonstrates how results of ipa-prop escape analysis from
> previous patches can be used at a later stage of compilation by
> directly returning them from gimple_call_arg_flags which currently
> relies on fnspec annotations.
>
> Bootstrapped and tested on x86_64-linux and also passes LTO bootstrap.
> I have only had a brief look at behavior of this in SPEC 2006 and for
> example in astar 1.19% of invocations of gimple_call_arg_flags return
> noescape where we previously never did and in calculix this increases
> from 15.62% (from annotations) to 18.14%. Noclobber flag is reported
> far less often still but for example in gamess that number raises from
> 5.21% to 7.66%.
>
> Thanks,
>
> Martin
>
>
> 2014-04-30 Martin Jambor <mjam...@suse.cz>
>
> * gimple.c: Include cgraph.h.
> (gimple_call_arg_flags): Also query bitmaps in cgraph_node.
>
> Index: src/gcc/gimple.c
> ===================================================================
> --- src.orig/gcc/gimple.c
> +++ src/gcc/gimple.c
> @@ -47,7 +47,7 @@ along with GCC; see the file COPYING3.
> #include "demangle.h"
> #include "langhooks.h"
> #include "bitmap.h"
> -
> +#include "cgraph.h"
>
> /* All the tuples have their operand vector (if present) at the very bottom
> of the structure. Therefore, the offset required to find the
> @@ -1349,32 +1349,50 @@ int
> gimple_call_arg_flags (const_gimple stmt, unsigned arg)
> {
> tree attr = gimple_call_fnspec (stmt);
> + int ret;
>
> - if (!attr || 1 + arg >= (unsigned) TREE_STRING_LENGTH (attr))
> - return 0;
> -
> - switch (TREE_STRING_POINTER (attr)[1 + arg])
> + if (attr && 1 + arg < (unsigned) TREE_STRING_LENGTH (attr))
> {
> - case 'x':
> - case 'X':
> - return EAF_UNUSED;
> -
> - case 'R':
> - return EAF_DIRECT | EAF_NOCLOBBER | EAF_NOESCAPE;
> -
> - case 'r':
> - return EAF_NOCLOBBER | EAF_NOESCAPE;
> -
> - case 'W':
> - return EAF_DIRECT | EAF_NOESCAPE;
> -
> - case 'w':
> - return EAF_NOESCAPE;
> + switch (TREE_STRING_POINTER (attr)[1 + arg])
> + {
> + case 'x':
> + case 'X':
> + ret = EAF_UNUSED;
> + break;
> + case 'R':
> + ret = EAF_DIRECT | EAF_NOCLOBBER | EAF_NOESCAPE;
> + break;
> + case 'r':
> + ret = EAF_NOCLOBBER | EAF_NOESCAPE;
> + break;
> + case 'W':
> + ret = EAF_DIRECT | EAF_NOESCAPE;
> + break;
> + case 'w':
> + ret = EAF_NOESCAPE;
> + break;
> + case '.':
> + default:
> + ret = 0;
> + }
> + }
> + else
> + ret = 0;
>
> - case '.':
> - default:
> - return 0;
> + tree callee_decl = gimple_call_fndecl (stmt);
> + if (callee_decl)
> + {
> + cgraph_node *callee_node = cgraph_get_node (callee_decl);
> + if (callee_node)
> + {
> + if (cgraph_param_noescape_p (callee_node, arg))
> + ret |= EAF_NOESCAPE;
> + if (cgraph_param_noclobber_p (callee_node, arg))
> + ret |= EAF_NOCLOBBER;
That's quite expensive. I guess we need a better way to store
those?
> + }
> }
> +
> + return ret;
> }
>
> /* Detects return flags for the call STMT. */
>
