+2014-11-03 Marc Glisse <marc.glisse@inria.fr>
+
+ PR tree-optimization/60770
+ * tree-into-ssa.c (rewrite_update_stmt): Return whether the
+ statement should be removed.
+ (maybe_register_def): Likewise. Replace clobbers with default
+ definitions.
+ (rewrite_dom_walker::before_dom_children): Remove statement if
+ rewrite_update_stmt says so.
+ * tree-ssa-live.c: Include tree-ssa.h.
+ (set_var_live_on_entry): Do not mark undefined variables as live.
+ (verify_live_on_entry): Do not check undefined variables.
+ * tree-ssa.h (ssa_undefined_value_p): New parameter for the case
+ of partially undefined variables.
+ * tree-ssa.c (ssa_undefined_value_p): Likewise.
+ (execute_update_addresses_taken): Do not drop clobbers.
+
2014-11-03 Marc Glisse <marc.glisse@inria.fr>
PR tree-optimization/63666
+2014-11-03 Marc Glisse <marc.glisse@inria.fr>
+
+ PR tree-optimization/60770
+ * gcc.dg/tree-ssa/pr60770-1.c: New file.
+
2014-11-03 Jan Beulich <jbeulich@suse.com>
* gcc.target/i386/i386.exp: Extend option set to test
--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-O -Wall" } */
+
+int f(int n){
+ int*p;
+ {
+ int yyy=n;
+ p=&yyy;
+ }
+ return *p; /* { dg-warning "yyy" } */
+}
/* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES
or OLD_SSA_NAMES, or if it is a symbol marked for renaming,
register it as the current definition for the names replaced by
- DEF_P. */
+ DEF_P. Returns whether the statement should be removed. */
-static inline void
+static inline bool
maybe_register_def (def_operand_p def_p, gimple stmt,
gimple_stmt_iterator gsi)
{
tree def = DEF_FROM_PTR (def_p);
tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def);
+ bool to_delete = false;
/* If DEF is a naked symbol that needs renaming, create a new
name for it. */
{
if (DECL_P (def))
{
- tree tracked_var;
-
- def = make_ssa_name (def, stmt);
+ if (gimple_clobber_p (stmt) && is_gimple_reg (sym))
+ {
+ gcc_checking_assert (TREE_CODE (sym) == VAR_DECL);
+ /* Replace clobber stmts with a default def. This new use of a
+ default definition may make it look like SSA_NAMEs have
+ conflicting lifetimes, so we need special code to let them
+ coalesce properly. */
+ to_delete = true;
+ def = get_or_create_ssa_default_def (cfun, sym);
+ }
+ else
+ def = make_ssa_name (def, stmt);
SET_DEF (def_p, def);
- tracked_var = target_for_debug_bind (sym);
+ tree tracked_var = target_for_debug_bind (sym);
if (tracked_var)
{
gimple note = gimple_build_debug_bind (tracked_var, def, stmt);
if (is_old_name (def))
register_new_update_single (def, def);
}
+
+ return to_delete;
}
OLD_SSA_NAMES used by SI will be updated to their current reaching
definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI
will be registered as a new definition for their corresponding name
- in OLD_SSA_NAMES. */
+ in OLD_SSA_NAMES. Returns whether STMT should be removed. */
-static void
+static bool
rewrite_update_stmt (gimple stmt, gimple_stmt_iterator gsi)
{
use_operand_p use_p;
/* Only update marked statements. */
if (!rewrite_uses_p (stmt) && !register_defs_p (stmt))
- return;
+ return false;
if (dump_file && (dump_flags & TDF_DETAILS))
{
/* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES.
Also register definitions for names whose underlying symbol is
marked for renaming. */
+ bool to_delete = false;
if (register_defs_p (stmt))
FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS)
- maybe_register_def (def_p, stmt, gsi);
+ to_delete |= maybe_register_def (def_p, stmt, gsi);
+
+ return to_delete;
}
if (bitmap_bit_p (interesting_blocks, bb->index))
{
gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index));
- for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- rewrite_update_stmt (gsi_stmt (gsi), gsi);
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
+ if (rewrite_update_stmt (gsi_stmt (gsi), gsi))
+ gsi_remove (&gsi, true);
+ else
+ gsi_next (&gsi);
}
/* Step 3. Update PHI nodes. */
#include "diagnostic-core.h"
#include "debug.h"
#include "flags.h"
+#include "tree-ssa.h"
#ifdef ENABLE_CHECKING
static void verify_live_on_entry (tree_live_info_p);
else
def_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun);
+ /* An undefined local variable does not need to be very alive. */
+ if (ssa_undefined_value_p (ssa_name, false))
+ return;
+
/* Visit each use of SSA_NAME and if it isn't in the same block as the def,
add it to the list of live on entry blocks. */
FOR_EACH_IMM_USE_FAST (use, imm_iter, ssa_name)
else
if (d == var)
{
+ /* An undefined local variable does not need to be very
+ alive. */
+ if (ssa_undefined_value_p (var, false))
+ continue;
+
/* The only way this var shouldn't be marked live on entry is
if it occurs in a PHI argument of the block. */
size_t z;
}
-/* Return true if T, an SSA_NAME, has an undefined value. */
+/* Return true if T, an SSA_NAME, has an undefined value. PARTIAL is what
+ should be returned if the value is only partially undefined. */
bool
-ssa_undefined_value_p (tree t)
+ssa_undefined_value_p (tree t, bool partial)
{
gimple def_stmt;
tree var = SSA_NAME_VAR (t);
return true;
/* Check if the complex was not only partially defined. */
- if (is_gimple_assign (def_stmt)
+ if (partial && is_gimple_assign (def_stmt)
&& gimple_assign_rhs_code (def_stmt) == COMPLEX_EXPR)
{
tree rhs1, rhs2;
if (gimple_assign_lhs (stmt) != lhs)
gimple_assign_set_lhs (stmt, lhs);
- /* For var ={v} {CLOBBER}; where var lost
- TREE_ADDRESSABLE just remove the stmt. */
- if (DECL_P (lhs)
- && TREE_CLOBBER_P (rhs)
- && bitmap_bit_p (suitable_for_renaming, DECL_UID (lhs)))
- {
- unlink_stmt_vdef (stmt);
- gsi_remove (&gsi, true);
- release_defs (stmt);
- continue;
- }
-
if (gimple_assign_rhs1 (stmt) != rhs)
{
gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
extern bool tree_ssa_useless_type_conversion (tree);
extern tree tree_ssa_strip_useless_type_conversions (tree);
-extern bool ssa_undefined_value_p (tree);
+extern bool ssa_undefined_value_p (tree, bool = true);
extern void execute_update_addresses_taken (void);
/* Given an edge_var_map V, return the PHI arg definition. */
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