This code dates before gimple tuples was around. So it uses both MODIFY_EXPR and
INDIRECT_REF :).
For `__builtin_va_start(ptr, 0)` it exands into:
```
_t = __builtin_next_arg (0);
*ptr = _t;
```
We need to get a new VDEF for the next arg call so we don't need to do a
ssa update too.
For `__builtin_va_copy(ptr, b)`, it expands into:
```
*ptr = b;
```
Which is still a store.
For `__builtin_va_end(ptr)`, we change it into a GIMPLE_NOP.
Since we don't return a value, we need to also set TODO_update_address_taken
on the todo manually too.
Note this code will be moved into gimple_fold later on. This is part of the
reason for updating this code. The other side is this simplifies the code
too.
gcc/ChangeLog:
* tree-ssa-ccp.cc (optimize_stdarg_builtin): Mannually create the
gimple statements instead of depending on the gimplifier.
(pass_fold_builtins::execute): Handle updated call to
optimize_stdarg_builtin.
Signed-off-by: Andrew Pinski <[email protected]>
---
gcc/tree-ssa-ccp.cc | 87 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 66 insertions(+), 21 deletions(-)
diff --git a/gcc/tree-ssa-ccp.cc b/gcc/tree-ssa-ccp.cc
index 389525b4be7..02da01ed565 100644
--- a/gcc/tree-ssa-ccp.cc
+++ b/gcc/tree-ssa-ccp.cc
@@ -3175,14 +3175,16 @@ optimize_stack_restore (gimple_stmt_iterator i)
/* If va_list type is a simple pointer and nothing special is needed,
optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0),
__builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple
- pointer assignment. */
+ pointer assignment. Returns true if a change happened. */
-static tree
-optimize_stdarg_builtin (gimple *call)
+static bool
+optimize_stdarg_builtin (gimple_stmt_iterator *gsi, gimple *call)
{
tree callee, lhs, rhs, cfun_va_list;
bool va_list_simple_ptr;
location_t loc = gimple_location (call);
+ gimple *nstmt0, *nstmt;
+ tree tlhs, oldvdef, newvdef;
callee = gimple_call_fndecl (call);
@@ -3197,48 +3199,90 @@ optimize_stdarg_builtin (gimple *call)
if (!va_list_simple_ptr
|| targetm.expand_builtin_va_start != NULL
|| !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG))
- return NULL_TREE;
+ return false;
if (gimple_call_num_args (call) != 2)
- return NULL_TREE;
+ return false;
lhs = gimple_call_arg (call, 0);
if (!POINTER_TYPE_P (TREE_TYPE (lhs))
|| TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs)))
!= TYPE_MAIN_VARIANT (cfun_va_list))
- return NULL_TREE;
+ return false;
+ /* Create `tlhs = __builtin_next_arg(0);`. */
+ tlhs = make_ssa_name (cfun_va_list);
+ nstmt0 = gimple_build_call (builtin_decl_explicit (BUILT_IN_NEXT_ARG),
1, integer_zero_node);
+ lhs = fold_build2 (MEM_REF, cfun_va_list, lhs, build_zero_cst (TREE_TYPE
(lhs)));
+ gimple_call_set_lhs (nstmt0, tlhs);
+ gimple_set_location (nstmt0, loc);
+ gimple_move_vops (nstmt0, call);
+ gsi_replace (gsi, nstmt0, false);
+ oldvdef = gimple_vdef (nstmt0);
+ newvdef = make_ssa_name (gimple_vop (cfun), nstmt0);
+ gimple_set_vdef (nstmt0, newvdef);
+
+ /* Create `*lhs = tlhs;`. */
+ nstmt = gimple_build_assign (lhs, tlhs);
+ gimple_set_location (nstmt, loc);
+ gimple_set_vuse (nstmt, newvdef);
+ gimple_set_vdef (nstmt, oldvdef);
+ SSA_NAME_DEF_STMT (oldvdef) = nstmt;
+ gsi_insert_after (gsi, nstmt, GSI_NEW_STMT);
- lhs = build_fold_indirect_ref_loc (loc, lhs);
- rhs = build_call_expr_loc (loc, builtin_decl_explicit
(BUILT_IN_NEXT_ARG),
- 1, integer_zero_node);
- rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs);
- return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Simplified\n ");
+ print_gimple_stmt (dump_file, call, 0, dump_flags);
+ fprintf (dump_file, "into\n ");
+ print_gimple_stmt (dump_file, nstmt0, 0, dump_flags);
+ fprintf (dump_file, " ");
+ print_gimple_stmt (dump_file, nstmt, 0, dump_flags);
+ }
+ return true;
case BUILT_IN_VA_COPY:
if (!va_list_simple_ptr)
- return NULL_TREE;
+ return false;
if (gimple_call_num_args (call) != 2)
- return NULL_TREE;
+ return false;
lhs = gimple_call_arg (call, 0);
if (!POINTER_TYPE_P (TREE_TYPE (lhs))
|| TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs)))
!= TYPE_MAIN_VARIANT (cfun_va_list))
- return NULL_TREE;
-
- lhs = build_fold_indirect_ref_loc (loc, lhs);
+ return false;
rhs = gimple_call_arg (call, 1);
if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs))
!= TYPE_MAIN_VARIANT (cfun_va_list))
- return NULL_TREE;
+ return false;
- rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs);
- return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs);
+ lhs = fold_build2 (MEM_REF, cfun_va_list, lhs, build_zero_cst (TREE_TYPE
(lhs)));
+ nstmt = gimple_build_assign (lhs, rhs);
+ gimple_set_location (nstmt, loc);
+ gimple_move_vops (nstmt, call);
+ gsi_replace (gsi, nstmt, false);
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Simplified\n ");
+ print_gimple_stmt (dump_file, call, 0, dump_flags);
+ fprintf (dump_file, "into\n ");
+ print_gimple_stmt (dump_file, nstmt, 0, dump_flags);
+ }
+ return true;
case BUILT_IN_VA_END:
/* No effect, so the statement will be deleted. */
- return integer_zero_node;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Removed\n ");
+ print_gimple_stmt (dump_file, call, 0, dump_flags);
+ }
+ unlink_stmt_vdef (call);
+ release_defs (call);
+ gsi_replace (gsi, gimple_build_nop (), true);
+ return true;
default:
gcc_unreachable ();
@@ -4431,7 +4475,8 @@ pass_fold_builtins::execute (function *fun)
case BUILT_IN_VA_END:
case BUILT_IN_VA_COPY:
/* These shouldn't be folded before pass_stdarg. */
- result = optimize_stdarg_builtin (stmt);
+ if (optimize_stdarg_builtin (&i, stmt))
+ todoflags |= TODO_update_address_taken;
break;
default:;
--
2.43.0
