Richard Biener <richard.guent...@gmail.com> wrote:
>On Thu, Oct 31, 2013 at 10:02 AM, Ilya Enkovich
><enkovich....@gmail.com> wrote:
>> Hi,
>>
>> Here is a patch which hadles the problem with optimization of
>BUILT_IN_CHKP_ARG_BND calls. Pointer Bounds Checker expects that
>argument of this call is a default SSA_NAME of the PARM_DECL whose
>bounds we want to get. The problem is in optimizations which may
>replace arg with it's copy or a known value. This patch suppress such
>modifications.
>
>This doesn't seem like a good fix. I suppose you require the same on
>RTL, that is, have the incoming arg reg coalesced with the use?
>In that case better set SSA_NAME_OCCURS_IN_ABNORMAL_PHI.
Btw, I would have chosen
P_2 = __builtin_xyz (p_1, bound)
Call (p_2)
Thus make the builtins a transparent pass-through which effectively binds
parameter to their bound, removing the need for the artificial arguments and
making propagations a non.issue
Also, how does the feature interact with other extensions such as nested
functions or optimizations like inlining?
Richard.
>Richard.
>
>> Thanks,
>> Ilya
>> --
>>
>> gcc/
>>
>> 2013-10-28 Ilya Enkovich <ilya.enkov...@intel.com>
>>
>> * tree-into-ssa.c: Include "target.h"
>> (rewrite_update_stmt): Skip BUILT_IN_CHKP_ARG_BND calls.
>> * tree-ssa-dom.c: Include "target.h"
>> (cprop_into_stmt): Skip BUILT_IN_CHKP_ARG_BND calls.
>>
>>
>> diff --git a/gcc/tree-into-ssa.c b/gcc/tree-into-ssa.c
>> index 981e9f4..8d48f6d 100644
>> --- a/gcc/tree-into-ssa.c
>> +++ b/gcc/tree-into-ssa.c
>> @@ -46,6 +46,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "params.h"
>> #include "diagnostic-core.h"
>> #include "tree-into-ssa.h"
>> +#include "target.h"
>>
>>
>> /* This file builds the SSA form for a function as described in:
>> @@ -1921,8 +1922,14 @@ rewrite_update_stmt (gimple stmt,
>gimple_stmt_iterator gsi)
>> }
>>
>> /* Rewrite USES included in OLD_SSA_NAMES and USES whose
>underlying
>> - symbol is marked for renaming. */
>> - if (rewrite_uses_p (stmt))
>> + symbol is marked for renaming.
>> + Skip calls to BUILT_IN_CHKP_ARG_BND whose arg should never be
>> + renamed. */
>> + if (rewrite_uses_p (stmt)
>> + && !(flag_check_pointer_bounds
>> + && (gimple_code (stmt) == GIMPLE_CALL)
>> + && gimple_call_fndecl (stmt)
>> + == targetm.builtin_chkp_function (BUILT_IN_CHKP_ARG_BND)))
>> {
>> if (is_gimple_debug (stmt))
>> {
>> diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
>> index 211bfcf..445278a 100644
>> --- a/gcc/tree-ssa-dom.c
>> +++ b/gcc/tree-ssa-dom.c
>> @@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "params.h"
>> #include "tree-ssa-threadedge.h"
>> #include "tree-ssa-dom.h"
>> +#include "target.h"
>>
>> /* This file implements optimizations on the dominator tree. */
>>
>> @@ -2266,6 +2267,16 @@ cprop_into_stmt (gimple stmt)
>> use_operand_p op_p;
>> ssa_op_iter iter;
>>
>> + /* Call used to obtain bounds of input arg by Pointer Bounds
>Checker
>> + should not be optimized. Argument of the call is a default
>> + SSA_NAME of PARM_DECL. It should never be replaced by value.
>*/
>> + if (flag_check_pointer_bounds && gimple_code (stmt) ==
>GIMPLE_CALL)
>> + {
>> + tree fndecl = gimple_call_fndecl (stmt);
>> + if (fndecl == targetm.builtin_chkp_function
>(BUILT_IN_CHKP_ARG_BND))
>> + return;
>> + }
>> +
>> FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_USE)
>> cprop_operand (stmt, op_p);
>> }
