While we should already be in loop-closed SSA form for virtual
operands most of the time (because we have a virtual use at
the return statement) and loop-closed SSA form for virtuals
is cheap (we only have a single virtual operand now) the following
makes sure that a loop-closed PHI node for virtuals does exist.
Nobody makes use of the fact but ISTR code that has code explicitely
dealing with the situation that virtuals are _not_ in loop-closed
SSA form.
Testing pending.
Richard.
2012-08-22 Richard Guenther <rguent...@suse.de>
* tree-ssa-loop-manip.c (add_exit_phis_var): Allow virtual operands.
(find_uses_to_rename_use): Likewise.
(find_uses_to_rename_bb): Likewise.
(find_uses_to_rename_stmt): Walk over all operands.
Index: gcc/tree-ssa-loop-manip.c
===================================================================
--- gcc/tree-ssa-loop-manip.c (revision 190590)
+++ gcc/tree-ssa-loop-manip.c (working copy)
@@ -303,8 +303,7 @@ add_exit_phis_var (tree var, bitmap use_
basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (var));
bitmap live_exits = BITMAP_ALLOC (&loop_renamer_obstack);
- gcc_checking_assert (! virtual_operand_p (var));
- gcc_assert (! bitmap_bit_p (use_blocks, def_bb->index));
+ gcc_checking_assert (! bitmap_bit_p (use_blocks, def_bb->index));
compute_live_loop_exits (live_exits, use_blocks, loop_exits, def_bb);
@@ -367,10 +366,6 @@ find_uses_to_rename_use (basic_block bb,
if (TREE_CODE (use) != SSA_NAME)
return;
- /* We don't need to keep virtual operands in loop-closed form. */
- if (virtual_operand_p (use))
- return;
-
ver = SSA_NAME_VERSION (use);
def_bb = gimple_bb (SSA_NAME_DEF_STMT (use));
if (!def_bb)
@@ -408,7 +403,7 @@ find_uses_to_rename_stmt (gimple stmt, b
if (is_gimple_debug (stmt))
return;
- FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
+ FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES)
find_uses_to_rename_use (bb, var, use_blocks, need_phis);
}
@@ -428,9 +423,8 @@ find_uses_to_rename_bb (basic_block bb,
for (bsi = gsi_start_phis (e->dest); !gsi_end_p (bsi); gsi_next (&bsi))
{
gimple phi = gsi_stmt (bsi);
- if (! virtual_operand_p (gimple_phi_result (phi)))
- find_uses_to_rename_use (bb, PHI_ARG_DEF_FROM_EDGE (phi, e),
- use_blocks, need_phis);
+ find_uses_to_rename_use (bb, PHI_ARG_DEF_FROM_EDGE (phi, e),
+ use_blocks, need_phis);
}
for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
