@@ -1,3 +1,9 @@
+2020-08-30 Sandra Loosemore <sandra@codesourcery.com>
+
+ * c-omp.c (annotate_for_loop): Move initializer processing...
+ (check_and_annotate_for_loop): ... to here. Allow the loop
+ variable as either operand to the condition.
+
2020-08-22 Sandra Loosemore <sandra@codesourcery.com>
Allow annotation of loops containing calls to builtins in
@@ -2479,86 +2479,26 @@ static tree (*lang_specific_unwrap_initializer) (tree);
/* Try to annotate the given NODE, which must be a FOR_STMT, with a
"#pragma acc loop auto" annotation. In practice, this means
- building an OMP_FOR node for it. PREV_STMT is the statement
- immediately before the loop, which may be used as the loop's
- initialization statement. Annotating the loop may fail, in which
- case INFO is used to record the cause of the failure and the
- original loop remains unchanged. This function returns the
- transformed loop if the transformation succeeded, the original node
- otherwise. */
+ building an OMP_FOR node for it. DECL and INIT are the
+ previously-verified iteration variable and initializer. Annotating
+ the loop may fail, in which case INFO is used to record the cause
+ of the failure and the original loop remains unchanged. This
+ function returns the transformed loop if the transformation
+ succeeded, the original node otherwise. */
static tree
-annotate_for_loop (tree node, tree_stmt_iterator *prev_tsi,
+annotate_for_loop (tree node, tree decl, tree init,
struct annotation_info *info)
{
gcc_checking_assert (TREE_CODE (node) == FOR_STMT);
location_t loc = EXPR_LOCATION (node);
tree cond = FOR_COND (node);
+ tree incr = FOR_EXPR (node);
+
+ gcc_assert (decl);
gcc_assert (cond);
- tree decl = TREE_OPERAND (cond, 0);
gcc_assert (decl && TREE_CODE (decl) == VAR_DECL);
- tree init = FOR_INIT_STMT (node);
- tree prev_stmt = NULL_TREE;
- bool unlink_prev = false;
- bool fix_decl = false;
-
-
- /* Both the C and C++ front ends normally put the initializer in the
- statement list just before the FOR_STMT instead of in FOR_INIT_STMT.
- If FOR_INIT_STMT happens to exist but isn't a MODIFY_EXPR, bail out
- because the code below won't handle it. */
- if (init != NULL_TREE && TREE_CODE (init) != MODIFY_EXPR)
- {
- do_not_annotate_loop (info, as_invalid_initializer, NULL_TREE);
- return node;
- }
-
- /* Examine the statement before the loop to see if it is a
- valid initializer. It must be either a MODIFY_EXPR or VAR_DECL,
- possibly wrapped in language-specific structure. */
- if (init == NULL_TREE && prev_tsi != NULL)
- {
- prev_stmt = tsi_stmt (*prev_tsi);
-
- /* Call the language-specific hook to unwrap prev_stmt. */
- if (prev_stmt)
- prev_stmt = (*lang_specific_unwrap_initializer) (prev_stmt);
-
- /* See if we have a valid MODIFY_EXPR. */
- if (prev_stmt
- && TREE_CODE (prev_stmt) == MODIFY_EXPR
- && TREE_OPERAND (prev_stmt, 0) == decl
- && !TREE_SIDE_EFFECTS (TREE_OPERAND (prev_stmt, 1)))
- {
- init = prev_stmt;
- unlink_prev = true;
- }
- else if (prev_stmt == decl
- && !TREE_SIDE_EFFECTS (DECL_INITIAL (decl)))
- {
- /* If the preceding statement is the declaration of the loop
- variable with its initialization, build an assignment
- expression for the loop's initializer. */
- init = build2 (MODIFY_EXPR, TREE_TYPE (decl), decl,
- DECL_INITIAL (decl));
- /* We need to remove the initializer from the decl if we
- end up using the init we just built instead. */
- fix_decl = true;
- }
- }
-
- if (init == NULL_TREE)
- /* There is nothing we can do to find the correct init statement for
- this loop, but c_finish_omp_for insists on having one and would fail
- otherwise. In that case, we would just return node. Do that
- directly, here. */
- {
- do_not_annotate_loop (info, as_missing_initializer, NULL_TREE);
- return node;
- }
-
- tree incr = FOR_EXPR (node);
/* The C++ frontend can wrap the increment two levels deep inside a
cleanup expression, but c_finish_omp_for does not care about that. */
@@ -2583,18 +2523,6 @@ annotate_for_loop (tree node, tree_stmt_iterator *prev_tsi,
NULL_TREE, false, info);
if (omp_for != NULL_TREE)
{
- if (unlink_prev)
- /* We don't need the previous statement that we consumed as an
- initializer in the new OMP_FOR any more. */
- tsi_delink (prev_tsi);
-
- if (fix_decl)
- /* We no longer need the initializer expression on the decl of
- the loop variable and don't want to duplicate it. The
- kernels conversion pass would interpret it as a stray
- assignment in a gang-single region. */
- DECL_INITIAL (prev_stmt) = NULL_TREE;
-
/* Add an auto clause, then return the new loop. */
tree auto_clause = build_omp_clause (loc, OMP_CLAUSE_AUTO);
OMP_CLAUSE_CHAIN (auto_clause) = OMP_FOR_CLAUSES (omp_for);
@@ -2620,11 +2548,16 @@ check_and_annotate_for_loop (tree *nodeptr, tree_stmt_iterator *prev_tsi,
{
tree node = *nodeptr;
gcc_assert (TREE_CODE (node) == FOR_STMT);
+ tree init = FOR_INIT_STMT (node);
+ tree cond = FOR_COND (node);
+ tree prev_stmt = NULL_TREE;
+ tree decl = NULL_TREE;
+ bool unlink_prev = false;
+ bool fix_decl = false;
/* This structure describes the current loop statement. */
struct annotation_info loop_info
= { node, NULL_TREE, false, as_in_kernels_loop, NULL_TREE, info };
- tree cond = FOR_COND (node);
/* If we are in the body of an explicitly-annotated loop, do not add
annotations to this loop or any other nested loops. */
@@ -2636,30 +2569,84 @@ check_and_annotate_for_loop (tree *nodeptr, tree_stmt_iterator *prev_tsi,
That is why we are doing some checks on the loop condition
that duplicate what c_finish_omp_for is doing. */
- /* The loop condition must be a comparison. */
+ /* First we need to find the decl and initializer for the
+ controlling variable. Both the C and C++ front ends normally put
+ the initializer in the statement list just before the FOR_STMT
+ instead of in FOR_INIT_STMT. If FOR_INIT_STMT happens to exist
+ but isn't a MODIFY_EXPR, give up.
+ handle it. */
+
+ else if (init != NULL_TREE && TREE_CODE (init) != MODIFY_EXPR)
+ do_not_annotate_loop (&loop_info, as_invalid_initializer, NULL_TREE);
+
+ /* Examine the statement before the loop to see if it is a
+ valid initializer. It must be either a MODIFY_EXPR or VAR_DECL,
+ possibly wrapped in language-specific structure. */
+ else if (init == NULL_TREE && prev_tsi != NULL && tsi_stmt (*prev_tsi))
+ {
+ prev_stmt = tsi_stmt (*prev_tsi);
+
+ /* Call the language-specific hook to unwrap prev_stmt. */
+ prev_stmt = (*lang_specific_unwrap_initializer) (prev_stmt);
+
+ /* See if we have a valid MODIFY_EXPR. */
+ if (TREE_CODE (prev_stmt) == MODIFY_EXPR
+ && is_local_var (TREE_OPERAND (prev_stmt, 0))
+ && !TREE_SIDE_EFFECTS (TREE_OPERAND (prev_stmt, 1)))
+ {
+ decl = TREE_OPERAND (prev_stmt, 0);
+ init = prev_stmt;
+ unlink_prev = true;
+ }
+ else if (is_local_var (prev_stmt)
+ && !TREE_SIDE_EFFECTS (DECL_INITIAL (prev_stmt)))
+ {
+ /* If the preceding statement is the declaration of the loop
+ variable with its initialization, build an assignment
+ expression for the loop's initializer. */
+ decl = prev_stmt;
+ init = build2 (MODIFY_EXPR, TREE_TYPE (decl), decl,
+ DECL_INITIAL (decl));
+ /* We need to remove the initializer from the decl if we
+ end up using the init we just built instead. */
+ fix_decl = true;
+ }
+ }
+
+ if (init == NULL_TREE || decl == NULL_TREE)
+ /* There is nothing we can do to find the correct init statement for
+ this loop. */
+ do_not_annotate_loop (&loop_info, as_missing_initializer, NULL_TREE);
+
+ /* The condition must be a comparison of the decl we found in
+ the initializer against an expression that can be hoisted
+ outside the loop. */
+ if (loop_info.state > as_in_kernels_loop)
+ /* Skip validating condition if we've already got an error. */
+ ;
else if (cond == NULL_TREE)
do_not_annotate_loop (&loop_info, as_missing_predicate, NULL_TREE);
else if (TREE_CODE_CLASS (TREE_CODE (cond)) != tcc_comparison)
do_not_annotate_loop (&loop_info, as_invalid_predicate, cond);
else
{
- /* The condition's LHS must be a local variable that does not
- have its address taken. Its RHS must also be such a local
- variable or a constant. */
- tree induction_var = TREE_OPERAND (cond, 0);
- tree limit_var = TREE_OPERAND (cond, 1);
- if (!is_local_var (induction_var)
- || (!is_local_var (limit_var)
- && (TREE_CODE_CLASS (TREE_CODE (limit_var))
- != tcc_constant)))
+ tree limit_exp = NULL_TREE;
+
+ if (TREE_OPERAND (cond, 0) == decl)
+ limit_exp = TREE_OPERAND (cond, 1);
+ else if (TREE_OPERAND (cond, 1) == decl)
+ limit_exp = TREE_OPERAND (cond, 0);
+
+ if (!limit_exp
+ || (!is_local_var (limit_exp)
+ && (TREE_CODE_CLASS (TREE_CODE (limit_exp)) != tcc_constant)))
do_not_annotate_loop (&loop_info, as_invalid_predicate, cond);
else
{
/* These variables must not be assigned to in the loop. */
- loop_info.vars = tree_cons (NULL_TREE, induction_var,
- loop_info.vars);
- if (TREE_CODE_CLASS (TREE_CODE (limit_var)) != tcc_constant)
- loop_info.vars = tree_cons (NULL_TREE, limit_var, loop_info.vars);
+ loop_info.vars = tree_cons (NULL_TREE, decl, loop_info.vars);
+ if (TREE_CODE_CLASS (TREE_CODE (limit_exp)) != tcc_constant)
+ loop_info.vars = tree_cons (NULL_TREE, limit_exp, loop_info.vars);
}
}
@@ -2674,11 +2661,24 @@ check_and_annotate_for_loop (tree *nodeptr, tree_stmt_iterator *prev_tsi,
/* If the traversal of the loop and all nested loops didn't hit
any problems, attempt the actual transformation. If it
succeeds, replace this node with the annotated loop. */
- tree result = annotate_for_loop (node, prev_tsi, &loop_info);
+ tree result = annotate_for_loop (node, decl, init, &loop_info);
if (result != node)
{
/* Success! */
*nodeptr = result;
+
+ if (unlink_prev)
+ /* We don't need the previous statement that we consumed
+ as an initializer in the new OMP_FOR any more. */
+ tsi_delink (prev_tsi);
+
+ if (fix_decl)
+ /* We no longer need the initializer expression on the
+ decl of the loop variable and don't want to duplicate
+ it. The kernels conversion pass would interpret it as
+ a stray assignment in a gang-single region. */
+ DECL_INITIAL (decl) = NULL_TREE;
+
return;
}
}