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[PATCH][alias-improvements] "Re-enable" SDSE
- From: Richard Guenther <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Date: Sun, 11 Jan 2009 15:35:56 +0100 (CET)
- Subject: [PATCH][alias-improvements] "Re-enable" SDSE
I managed to break (read: make it a no-op) simple DSE by always recording
a load for every store. Oops. It turns out this skews inlining for
tramp3d quite a lot, so this patch improves tramp3d performance by 20%,
not quite to the trunk level though.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to the
branch.
Richard.
2009-01-11 Richard Guenther <rguenther@suse.de>
* tree-ssa-operands.h (unlink_stmt_vdef): Declare.
* tree-ssa-dse.c (dse_optimize_stmt): Use it.
(execute_simple_dse): Likewise. Make sure to update virtual
SSA form if we changed a call.
* tree-ssa-operands.c (add_stmt_operand): For defs do not
update the bitmap of loaded syms.
(unlink_stmt_vdef): New function.
Index: gcc/tree-ssa-operands.h
===================================================================
*** gcc/tree-ssa-operands.h.orig 2009-01-11 14:22:00.000000000 +0100
--- gcc/tree-ssa-operands.h 2009-01-11 14:23:26.000000000 +0100
*************** extern void push_stmt_changes (gimple *)
*** 216,221 ****
--- 216,223 ----
extern void pop_stmt_changes (gimple *);
extern void discard_stmt_changes (gimple *);
+ extern void unlink_stmt_vdef (gimple);
+
enum ssa_op_iter_type {
ssa_op_iter_none = 0,
ssa_op_iter_tree,
Index: gcc/tree-ssa-dse.c
===================================================================
*** gcc/tree-ssa-dse.c.orig 2009-01-11 14:22:00.000000000 +0100
--- gcc/tree-ssa-dse.c 2009-01-11 14:23:26.000000000 +0100
*************** dse_optimize_stmt (struct dom_walk_data
*** 312,332 ****
}
/* Then we need to fix the operand of the consuming stmt. */
! if (gimple_vdef (stmt))
! {
! use_operand_p use_p;
! imm_use_iterator iter;
! gimple use_stmt;
!
! FOR_EACH_IMM_USE_STMT (use_stmt, iter, gimple_vdef (stmt))
! {
! FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
! SET_USE (use_p, gimple_vuse (stmt));
! }
!
! if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt)))
! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vuse (stmt)) = 1;
! }
/* Remove the dead store. */
gsi_remove (&gsi, true);
--- 312,318 ----
}
/* Then we need to fix the operand of the consuming stmt. */
! unlink_stmt_vdef (stmt);
/* Remove the dead store. */
gsi_remove (&gsi, true);
*************** execute_simple_dse (void)
*** 504,511 ****
bitmap_iterator bi;
bool dead = true;
-
-
/* See if STMT only stores to write-only variables and
verify that there are no volatile operands. tree-ssa-operands
sets has_volatile_ops flag for all statements involving
--- 490,495 ----
*************** execute_simple_dse (void)
*** 555,560 ****
--- 539,545 ----
push_stmt_changes (gsi_stmt_ptr (&gsi));
gimple_call_set_lhs (stmt, NULL);
pop_stmt_changes (gsi_stmt_ptr (&gsi));
+ todo |= TODO_update_ssa_only_virtuals;
}
else
{
*************** execute_simple_dse (void)
*** 565,570 ****
--- 550,556 ----
fprintf (dump_file, "'\n");
}
removed = true;
+ unlink_stmt_vdef (stmt);
gsi_remove (&gsi, true);
todo |= TODO_cleanup_cfg;
}
Index: gcc/tree-ssa-operands.c
===================================================================
*** gcc/tree-ssa-operands.c.orig 2009-01-11 14:22:01.000000000 +0100
--- gcc/tree-ssa-operands.c 2009-01-11 14:23:26.000000000 +0100
*************** add_stmt_operand (tree *var_p, gimple st
*** 1194,1200 ****
{
if (flags & opf_def)
bitmap_set_bit (build_stores, DECL_UID (var));
! bitmap_set_bit (build_loads, DECL_UID (var));
}
add_virtual_operand (stmt, flags);
}
--- 1194,1201 ----
{
if (flags & opf_def)
bitmap_set_bit (build_stores, DECL_UID (var));
! else
! bitmap_set_bit (build_loads, DECL_UID (var));
}
add_virtual_operand (stmt, flags);
}
*************** discard_stmt_changes (gimple *stmt_p)
*** 2209,2211 ****
--- 2210,2237 ----
buf->stmt_p = NULL;
free (buf);
}
+
+ /* Unlink STMTs virtual definition from the IL by propagating its use. */
+
+ void
+ unlink_stmt_vdef (gimple stmt)
+ {
+ use_operand_p use_p;
+ imm_use_iterator iter;
+ gimple use_stmt;
+ tree vdef = gimple_vdef (stmt);
+
+ if (!vdef
+ || TREE_CODE (vdef) != SSA_NAME)
+ return;
+
+ FOR_EACH_IMM_USE_STMT (use_stmt, iter, gimple_vdef (stmt))
+ {
+ FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+ SET_USE (use_p, gimple_vuse (stmt));
+ }
+
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt)))
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vuse (stmt)) = 1;
+ }
+