[PATCH, Pointer Bounds Checker 14/x] Passes [8/n] Remove useless builtin calls

[Ilya Enkovich]

Hi,

This patch adds removal of user calls to chkp builtins which become useless after instrumentation.

Thanks,
Ilya
--
2014-10-08 Ilya Enkovich <***@intel.com>

* tree-chkp.c (chkp_remove_useless_builtins): New.
(chkp_execute): Remove useless calls to Pointer Bounds
Checker builtins.


diff --git a/gcc/tree-chkp.c b/gcc/tree-chkp.c
index 5443950..b424af8 100644
--- a/gcc/tree-chkp.c
+++ b/gcc/tree-chkp.c
@@ -3805,6 +3805,49 @@ chkp_instrument_function (void)
}
}

+/* Find init/null/copy_ptr_bounds calls and replace them
+ with assignments. It should allow better code
+ optimization. */
+
+static void
+chkp_remove_useless_builtins ()
+{
+ basic_block bb, next;
+ gimple_stmt_iterator gsi;
+
+ bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb;
+ do
+ {
+ next = bb->next_bb;
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+ tree fndecl;
+ enum built_in_function fcode;
+
+ /* Find builtins returning first arg and replace
+ them with assignments. */
+ if (gimple_code (stmt) == GIMPLE_CALL
+ && (fndecl = gimple_call_fndecl (stmt))
+ && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
+ && (fcode = DECL_FUNCTION_CODE (fndecl))
+ && (fcode == BUILT_IN_CHKP_INIT_PTR_BOUNDS
+ || fcode == BUILT_IN_CHKP_NULL_PTR_BOUNDS
+ || fcode == BUILT_IN_CHKP_COPY_PTR_BOUNDS
+ || fcode == BUILT_IN_CHKP_SET_PTR_BOUNDS))
+ {
+ tree res = gimple_call_arg (stmt, 0);
+ if (!update_call_from_tree (&gsi, res))
+ gimplify_and_update_call_from_tree (&gsi, res);
+ stmt = gsi_stmt (gsi);
+ update_stmt (stmt);
+ }
+ }
+ bb = next;
+ }
+ while (bb);
+}
+
/* Initialize pass. */
static void
chkp_init (void)
@@ -3872,6 +3915,8 @@ chkp_execute (void)

chkp_instrument_function ();

+ chkp_remove_useless_builtins ();
+
chkp_function_mark_instrumented (cfun->decl);

chkp_fix_cfg ();