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Support EAF_NOT_RETURNED in tree-ssa-structalias

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gcc/ChangeLog:

2021-07-17  Jan Hubicka  <hubicka@ucw.cz>

	* tree-ssa-structalias.c (handle_rhs_call): Support EAF_NOT_RETURNED.
	(handle_const_call): Liekise
	(handle_pure_call): Liekise

gcc/testsuite/ChangeLog:

2021-07-17  Jan Hubicka  <hubicka@ucw.cz>

	* gcc.dg/tree-ssa/modref-6.c: New test.
This commit is contained in:
Jan Hubicka 2021-07-17 14:24:19 +02:00
parent 704e8a825c
commit 0103d18dfc
2 changed files with 59 additions and 8 deletions
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37
gcc/testsuite/gcc.dg/tree-ssa/modref-6.c Normal file
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@ -0,0 +1,37 @@
/* { dg-options "-O2 -fdump-tree-modref1 -fdump-tree-optimized" } */
/* { dg-do compile } */
int c;
__attribute__ ((noinline))
int *test (int *b)
{
c++;
return *b ? &c : 0;
}
__attribute__ ((noinline, pure))
int *pure_test (int *b)
{
return *b && c ? &c : 0;
}
__attribute__ ((noinline, const))
int *const_test (int *b)
{
return b ? &c : 0;
}
void escape (int *);
int test2()
{
int a = 42;
escape (test (&a));
escape (pure_test (&a));
escape (const_test (&a));
return a;
}
/* Flags for normal call. */
/* { dg-final { scan-tree-dump "parm 0 flags: direct noclobber noescape nodirectescape not_returned" "modref1" } } */
/* Flags for pure call. */
/* { dg-final { scan-tree-dump "parm 0 flags: direct not_returned" "modref1" } } */
/* Flags for const call. */
/* { dg-final { scan-tree-dump "parm 0 flags: unused not_returned" "modref1" } } */
/* Overall we want to make "int a" non escaping. */
/* { dg-final { scan-tree-dump "return 42" "optimized" } } */

30
gcc/tree-ssa-structalias.c
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@ -4082,9 +4082,12 @@ handle_rhs_call (gcall *stmt, vec<ce_s> *results)
if (!(flags & EAF_DIRECT))
make_transitive_closure_constraints (tem);
make_copy_constraint (uses, tem->id);
/* TODO: This is overly conservative when some parameters are
returned while others are not. */
if (!(flags & EAF_NOT_RETURNED))
returns_uses = true;
if (!(flags & (EAF_NOESCAPE | EAF_DIRECT)))
make_indirect_escape_constraint (tem);
returns_uses = true;
}
else if (flags & (EAF_NOESCAPE | EAF_NODIRECTESCAPE))
{
@ -4098,6 +4101,8 @@ handle_rhs_call (gcall *stmt, vec<ce_s> *results)
if (!(flags & EAF_DIRECT))
make_transitive_closure_constraints (tem);
make_copy_constraint (uses, tem->id);
if (!(flags & EAF_NOT_RETURNED))
returns_uses = true;
make_copy_constraint (clobbers, tem->id);
/* Add *tem = nonlocal, do not add *tem = callused as
EAF_NOESCAPE parameters do not escape to other parameters
@ -4111,7 +4116,6 @@ handle_rhs_call (gcall *stmt, vec<ce_s> *results)
process_constraint (new_constraint (lhs, rhs));
if (!(flags & (EAF_NOESCAPE | EAF_DIRECT)))
make_indirect_escape_constraint (tem);
returns_uses = true;
}
else
make_escape_constraint (arg);
@ -4261,13 +4265,18 @@ handle_const_call (gcall *stmt, vec<ce_s> *results)
/* May return offsetted arguments. */
varinfo_t tem = NULL;
if (gimple_call_num_args (stmt) != 0)
{
tem = new_var_info (NULL_TREE, "callarg", true);
tem->is_reg_var = true;
}
for (k = 0; k < gimple_call_num_args (stmt); ++k)
{
int flags = gimple_call_arg_flags (stmt, k);
/* If the argument is not used or not returned we can ignore it. */
if (flags & (EAF_UNUSED | EAF_NOT_RETURNED))
continue;
if (!tem)
{
tem = new_var_info (NULL_TREE, "callarg", true);
tem->is_reg_var = true;
}
tree arg = gimple_call_arg (stmt, k);
auto_vec<ce_s> argc;
get_constraint_for_rhs (arg, &argc);
@ -4298,6 +4307,7 @@ handle_pure_call (gcall *stmt, vec<ce_s> *results)
struct constraint_expr rhsc;
unsigned i;
varinfo_t uses = NULL;
bool record_uses = false;
/* Memory reached from pointer arguments is call-used. */
for (i = 0; i < gimple_call_num_args (stmt); ++i)
@ -4315,6 +4325,8 @@ handle_pure_call (gcall *stmt, vec<ce_s> *results)
make_transitive_closure_constraints (uses);
}
make_constraint_to (uses->id, arg);
if (!(flags & EAF_NOT_RETURNED))
record_uses = true;
}
/* The static chain is used as well. */
@ -4327,6 +4339,7 @@ handle_pure_call (gcall *stmt, vec<ce_s> *results)
make_transitive_closure_constraints (uses);
}
make_constraint_to (uses->id, gimple_call_chain (stmt));
record_uses = true;
}
/* And if we applied NRV the address of the return slot. */
@ -4343,10 +4356,11 @@ handle_pure_call (gcall *stmt, vec<ce_s> *results)
auto_vec<ce_s> tmpc;
get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
make_constraints_to (uses->id, tmpc);
record_uses = true;
}
/* Pure functions may return call-used and nonlocal memory. */
if (uses)
if (record_uses)
{
rhsc.var = uses->id;
rhsc.offset = 0;