return true;
}
-/* Return true if STMT can be put back into INNER, a loop by moving it to the
- beginning of that loop. */
+/* Return true if STMT can be put back into the loop INNER, by
+ copying it to the beginning of that loop and changing the uses. */
static bool
can_put_in_inner_loop (struct loop *inner, tree stmt)
{
imm_use_iterator imm_iter;
use_operand_p use_p;
- basic_block use_bb = NULL;
gcc_assert (TREE_CODE (stmt) == MODIFY_EXPR);
if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)
|| !expr_invariant_in_loop_p (inner, TREE_OPERAND (stmt, 1)))
return false;
- /* We require that the basic block of all uses be the same, or the use be an
- exit phi. */
FOR_EACH_IMM_USE_FAST (use_p, imm_iter, TREE_OPERAND (stmt, 0))
{
if (!exit_phi_for_loop_p (inner, USE_STMT (use_p)))
if (!flow_bb_inside_loop_p (inner, immbb))
return false;
- if (use_bb == NULL)
- use_bb = immbb;
- else if (immbb != use_bb)
+ }
+ }
+ return true;
+}
+
+/* Return true if STMT can be put *after* the inner loop of LOOP. */
+static bool
+can_put_after_inner_loop (struct loop *loop, tree stmt)
+{
+ imm_use_iterator imm_iter;
+ use_operand_p use_p;
+
+ if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
+ return false;
+
+ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, TREE_OPERAND (stmt, 0))
+ {
+ if (!exit_phi_for_loop_p (loop, USE_STMT (use_p)))
+ {
+ basic_block immbb = bb_for_stmt (USE_STMT (use_p));
+
+ if (!dominated_by_p (CDI_DOMINATORS,
+ immbb,
+ loop->inner->header)
+ && !can_put_in_inner_loop (loop->inner, stmt))
return false;
}
}
return true;
-
}
+
/* Return TRUE if LOOP is an imperfect nest that we can convert to a perfect
one. LOOPIVS is a vector of induction variables, one per loop.
ATM, we only handle imperfect nests of depth 2, where all of the statements
if (stmt_uses_op (stmt, iv))
goto fail;
- /* If this is a simple operation like a cast that is invariant
- in the inner loop, only used there, and we can place it
- there, then it's not going to hurt us.
- This means that we will propagate casts and other cheap
- invariant operations *back*
- into the inner loop if we can interchange the loop, on the
- theory that we are going to gain a lot more by interchanging
- the loop than we are by leaving some invariant code there for
- some other pass to clean up. */
+ /* If this is a simple operation like a cast that is
+ invariant in the inner loop, or after the inner loop,
+ then see if we can place it back where it came from.
+ This means that we will propagate casts and other
+ cheap invariant operations *back* into or after
+ the inner loop if we can interchange the loop, on the
+ theory that we are going to gain a lot more by
+ interchanging the loop than we are by leaving some
+ invariant code there for some other pass to clean
+ up. */
if (TREE_CODE (stmt) == MODIFY_EXPR
&& is_gimple_cast (TREE_OPERAND (stmt, 1))
- && can_put_in_inner_loop (loop->inner, stmt))
+ && (can_put_in_inner_loop (loop->inner, stmt)
+ || can_put_after_inner_loop (loop, stmt)))
continue;
/* Otherwise, if the bb of a statement we care about isn't
bsi_prev (&bsi);
continue;
}
- /* Move this statement back into the inner loop.
- This looks a bit confusing, but we are really just
- finding the first non-exit phi use and moving the
- statement to the beginning of that use's basic
- block. */
+
+ /* Make copies of this statement to put it back next
+ to its uses. */
FOR_EACH_IMM_USE_SAFE (use_p, imm_iter,
TREE_OPERAND (stmt, 0))
{
tree imm_stmt = USE_STMT (use_p);
if (!exit_phi_for_loop_p (loop->inner, imm_stmt))
{
- block_stmt_iterator tobsi = bsi_after_labels (bb_for_stmt (imm_stmt));
- bsi_move_after (&bsi, &tobsi);
- update_stmt (stmt);
- BREAK_FROM_SAFE_IMM_USE (imm_iter);
+ block_stmt_iterator tobsi;
+ tree newname;
+ tree newstmt;
+
+ newstmt = unshare_expr (stmt);
+ tobsi = bsi_after_labels (bb_for_stmt (imm_stmt));
+ newname = TREE_OPERAND (newstmt, 0);
+ newname = SSA_NAME_VAR (newname);
+ newname = make_ssa_name (newname, newstmt);
+ TREE_OPERAND (newstmt, 0) = newname;
+ SET_USE (use_p, TREE_OPERAND (newstmt, 0));
+ bsi_insert_after (&tobsi, newstmt, BSI_SAME_STMT);
+ update_stmt (newstmt);
+ update_stmt (imm_stmt);
}
}
+ if (!bsi_end_p (bsi))
+ bsi_prev (&bsi);
}
}
else
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