Hi,
Honza requested that we do attempt to produce pass-through jump
functions even when the actual formal parameter that is being passed
on is addressable - provided that we can prove it has not changed
value, of course. The following patch does this, hopefully the
limitations of our parameter-not-modified mechanism are not too strict
for this purpose.
The patch is supposed to be applied on top of the one I have just sent
that renames all parm_infos to parm_ainfos. I have successfully
bootstrapped and tested it on x86_64-linux.
OK for trunk?
Thanks,
Martin
2011-10-26 Martin Jambor <mjam...@suse.cz>
* ipa-prop.c (mark_modified): Moved up in the file.
(is_parm_modified_before_call): Renamed to
is_parm_modified_before_stmt, moved up in the file.
(load_from_unmodified_param): New function.
(compute_complex_assign_jump_func): Also attempt to create pass
through jump functions for values loaded from (addressable)
parameters.
* testsuite/gcc.dg/ipa/ipcp-4.c: New test.
Index: src/gcc/testsuite/gcc.dg/ipa/ipcp-4.c
===================================================================
--- /dev/null
+++ src/gcc/testsuite/gcc.dg/ipa/ipcp-4.c
@@ -0,0 +1,68 @@
+/* Test that IPA-CP is able to produce a pass-through jump function for the
+ call of g1 and g2 even though a is addressable. Also test that h is not
+ cloned. */
+
+/* { dg-do compile } */
+/* { dg-options "-O3 -fipa-cp -fipa-cp-clone -fdump-ipa-cp
-fno-early-inlining" } */
+/* { dg-add-options bind_pic_locally } */
+
+extern void use_stuff (int);
+extern void use_pointer (int *);
+
+static int
+h (int a, int b)
+{
+ int i;
+
+ for (i = 8; i <= b; i++)
+ use_stuff (a+8);
+}
+
+static int
+g1 (int a, int b)
+{
+ int i;
+
+ for (i = 0; i <= b; i++)
+ use_pointer (&a);
+ h (a, b);
+}
+
+static int
+g2 (int a, int b)
+{
+ int i;
+
+ for (i = 4; i <= b; i += 2)
+ use_stuff (a);
+}
+
+
+static void
+f (int a, int z)
+{
+ if (z > 1)
+ g1 (a, z);
+ else
+ g2 (a + 4, z);
+ use_pointer (&a);
+}
+
+int
+main (int argc, char *argv[])
+{
+ int i;
+ for (i = 0; i < 100; i++)
+ f (7, argc);
+ return 0;
+}
+
+
+/* { dg-final { scan-ipa-dump "Creating a specialized node of g1.*for all
known contexts" "cp" } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of g2.*for all
known contexts" "cp" } } */
+/* { dg-final { scan-ipa-dump-not "Creating a specialized node of h.*for all
known contexts" "cp" } } */
+/* { dg-final { scan-ipa-dump-times "replacing param a with const 7" 2 "cp" }
} */
+/* { dg-final { scan-ipa-dump "replacing param a with const 11" "cp" } } */
+/* { dg-final { cleanup-ipa-dump "cp" } } */
+
+
Index: src/gcc/ipa-prop.c
===================================================================
--- src.orig/gcc/ipa-prop.c
+++ src/gcc/ipa-prop.c
@@ -419,31 +419,105 @@ detect_type_change_ssa (tree arg, gimple
return detect_type_change (arg, arg, call, jfunc, 0);
}
+/* Callback of walk_aliased_vdefs. Flags that it has been invoked to the
+ boolean variable pointed to by DATA. */
+
+static bool
+mark_modified (ao_ref *ao ATTRIBUTE_UNUSED, tree vdef ATTRIBUTE_UNUSED,
+ void *data)
+{
+ bool *b = (bool *) data;
+ *b = true;
+ return true;
+}
+
+/* Return true if the formal parameter PARM might have been modified in this
+ function before reaching the statement STMT. PARM_AINFO is a pointer to a
+ structure containing temporary information about PARM. */
+
+static bool
+is_parm_modified_before_stmt (struct param_analysis_info *parm_ainfo,
+ gimple stmt, tree parm)
+{
+ bool modified = false;
+ ao_ref refd;
+
+ if (parm_ainfo->modified)
+ return true;
+
+ ao_ref_init (&refd, parm);
+ walk_aliased_vdefs (&refd, gimple_vuse (stmt), mark_modified,
+ &modified, &parm_ainfo->visited_statements);
+ if (modified)
+ {
+ parm_ainfo->modified = true;
+ return true;
+ }
+ return false;
+}
+
+/* If STMT is an assignment that loads a value from an parameter declaration,
+ return the index of the parameter in ipa_node_params which has not been
+ modified. Otherwise return -1. */
+
+static int
+load_from_unmodified_param (struct ipa_node_params *info,
+ struct param_analysis_info *parms_ainfo,
+ gimple stmt)
+{
+ int index;
+ tree op1;
+
+ if (!gimple_assign_single_p (stmt)
+ || gimple_assign_cast_p (stmt))
+ return -1;
+
+ op1 = gimple_assign_rhs1 (stmt);
+ index = ipa_get_param_decl_index (info, op1);
+ if (index < 0
+ || is_parm_modified_before_stmt (&parms_ainfo[index], stmt, op1))
+ return -1;
+
+ return index;
+}
/* Given that an actual argument is an SSA_NAME (given in NAME) and is a result
of an assignment statement STMT, try to find out whether NAME can be
described by a (possibly polynomial) pass-through jump-function or an
- ancestor jump function and if so, write the appropriate function into
- JFUNC */
+ ancestor jump function and if so, write the appropriate function into JFUNC.
+ PARMS_AINFO describes state of analysis with respect to individual formal
+ parameters. */
static void
compute_complex_assign_jump_func (struct ipa_node_params *info,
+ struct param_analysis_info *parms_ainfo,
struct ipa_jump_func *jfunc,
gimple call, gimple stmt, tree name)
{
HOST_WIDE_INT offset, size, max_size;
- tree op1, op2, base, ssa;
+ tree op1, tc_ssa, base, ssa;
int index;
op1 = gimple_assign_rhs1 (stmt);
- op2 = gimple_assign_rhs2 (stmt);
- if (TREE_CODE (op1) == SSA_NAME
- && SSA_NAME_IS_DEFAULT_DEF (op1))
+ if (TREE_CODE (op1) == SSA_NAME)
{
- index = ipa_get_param_decl_index (info, SSA_NAME_VAR (op1));
- if (index < 0)
- return;
+ if (SSA_NAME_IS_DEFAULT_DEF (op1))
+ index = ipa_get_param_decl_index (info, SSA_NAME_VAR (op1));
+ else
+ index = load_from_unmodified_param (info, parms_ainfo,
+ SSA_NAME_DEF_STMT (op1));
+ tc_ssa = op1;
+ }
+ else
+ {
+ index = load_from_unmodified_param (info, parms_ainfo, stmt);
+ tc_ssa = gimple_assign_lhs (stmt);
+ }
+
+ if (index >= 0)
+ {
+ tree op2 = gimple_assign_rhs2 (stmt);
if (op2)
{
@@ -458,8 +532,9 @@ compute_complex_assign_jump_func (struct
jfunc->value.pass_through.operation = gimple_assign_rhs_code (stmt);
jfunc->value.pass_through.operand = op2;
}
- else if (gimple_assign_unary_nop_p (stmt)
- && !detect_type_change_ssa (op1, call, jfunc))
+ else if (gimple_assign_single_p (stmt)
+ && !gimple_assign_cast_p (stmt)
+ && !detect_type_change_ssa (tc_ssa, call, jfunc))
{
jfunc->type = IPA_JF_PASS_THROUGH;
jfunc->value.pass_through.formal_id = index;
@@ -665,12 +740,14 @@ compute_known_type_jump_func (tree op, s
/* Determine the jump functions of scalar arguments. Scalar means SSA names
and constants of a number of selected types. INFO is the ipa_node_params
- structure associated with the caller, FUNCTIONS is a pointer to an array of
- jump function structures associated with CALL which is the call statement
- being examined.*/
+ structure associated with the caller, PARMS_AINFO describes state of
+ analysis with respect to individual formal parameters. ARGS is the
+ ipa_edge_args structure describing the callsite CALL which is the call
+ statement being examined.*/
static void
compute_scalar_jump_functions (struct ipa_node_params *info,
+ struct param_analysis_info *parms_ainfo,
struct ipa_edge_args *args,
gimple call)
{
@@ -705,7 +782,8 @@ compute_scalar_jump_functions (struct ip
{
gimple stmt = SSA_NAME_DEF_STMT (arg);
if (is_gimple_assign (stmt))
- compute_complex_assign_jump_func (info, jfunc, call, stmt, arg);
+ compute_complex_assign_jump_func (info, parms_ainfo, jfunc,
+ call, stmt, arg);
else if (gimple_code (stmt) == GIMPLE_PHI)
compute_complex_ancestor_jump_func (info, jfunc, call, stmt);
}
@@ -748,43 +826,6 @@ type_like_member_ptr_p (tree type, tree
return true;
}
-/* Callback of walk_aliased_vdefs. Flags that it has been invoked to the
- boolean variable pointed to by DATA. */
-
-static bool
-mark_modified (ao_ref *ao ATTRIBUTE_UNUSED, tree vdef ATTRIBUTE_UNUSED,
- void *data)
-{
- bool *b = (bool *) data;
- *b = true;
- return true;
-}
-
-/* Return true if the formal parameter PARM might have been modified in this
- function before reaching the statement CALL. PARM_INFO is a pointer to a
- structure containing intermediate information about PARM. */
-
-static bool
-is_parm_modified_before_call (struct param_analysis_info *parm_info,
- gimple call, tree parm)
-{
- bool modified = false;
- ao_ref refd;
-
- if (parm_info->modified)
- return true;
-
- ao_ref_init (&refd, parm);
- walk_aliased_vdefs (&refd, gimple_vuse (call), mark_modified,
- &modified, &parm_info->visited_statements);
- if (modified)
- {
- parm_info->modified = true;
- return true;
- }
- return false;
-}
-
/* Go through arguments of the CALL and for every one that looks like a member
pointer, check whether it can be safely declared pass-through and if so,
mark that to the corresponding item of jump FUNCTIONS. Return true iff
@@ -813,7 +854,7 @@ compute_pass_through_member_ptrs (struct
int index = ipa_get_param_decl_index (info, arg);
gcc_assert (index >=0);
- if (!is_parm_modified_before_call (&parms_ainfo[index], call,
+ if (!is_parm_modified_before_stmt (&parms_ainfo[index], call,
arg))
{
struct ipa_jump_func *jfunc = ipa_get_ith_jump_func (args,
@@ -982,7 +1023,7 @@ ipa_compute_jump_functions_for_edge (str
VEC_safe_grow_cleared (ipa_jump_func_t, gc, args->jump_functions, arg_num);
/* We will deal with constants and SSA scalars first: */
- compute_scalar_jump_functions (info, args, call);
+ compute_scalar_jump_functions (info, parms_ainfo, args, call);
/* Let's check whether there are any potential member pointers and if so,
whether we can determine their functions as pass_through. */
@@ -1284,7 +1325,7 @@ ipa_analyze_indirect_call_uses (struct c
return;
index = ipa_get_param_decl_index (info, rec);
- if (index >= 0 && !is_parm_modified_before_call (&parms_ainfo[index],
+ if (index >= 0 && !is_parm_modified_before_stmt (&parms_ainfo[index],
call, rec))
ipa_note_param_call (node, index, call);
