+/* Code callback function for converting
+ do while(a)
+ end do
+ into the equivalent
+ do
+ if (.not. a) exit
+ end do
+ This is because common function elimination would otherwise place the
+ temporary variables outside the loop. */
+
+static int
+convert_do_while (gfc_code **c, int *walk_subtrees ATTRIBUTE_UNUSED,
+ void *data ATTRIBUTE_UNUSED)
+{
+ gfc_code *co = *c;
+ gfc_code *c_if1, *c_if2, *c_exit;
+ gfc_code *loopblock;
+ gfc_expr *e_not, *e_cond;
+
+ if (co->op != EXEC_DO_WHILE)
+ return 0;
+
+ if (co->expr1 == NULL || co->expr1->expr_type == EXPR_CONSTANT)
+ return 0;
+
+ e_cond = co->expr1;
+
+ /* Generate the condition of the if statement, which is .not. the original
+ statement. */
+ e_not = gfc_get_expr ();
+ e_not->ts = e_cond->ts;
+ e_not->where = e_cond->where;
+ e_not->expr_type = EXPR_OP;
+ e_not->value.op.op = INTRINSIC_NOT;
+ e_not->value.op.op1 = e_cond;
+
+ /* Generate the EXIT statement. */
+ c_exit = XCNEW (gfc_code);
+ c_exit->op = EXEC_EXIT;
+ c_exit->ext.which_construct = co;
+ c_exit->loc = co->loc;
+
+ /* Generate the IF statement. */
+ c_if2 = XCNEW (gfc_code);
+ c_if2->op = EXEC_IF;
+ c_if2->expr1 = e_not;
+ c_if2->next = c_exit;
+ c_if2->loc = co->loc;
+
+ /* ... plus the one to chain it to. */
+ c_if1 = XCNEW (gfc_code);
+ c_if1->op = EXEC_IF;
+ c_if1->block = c_if2;
+ c_if1->loc = co->loc;
+
+ /* Make the DO WHILE loop into a DO block by replacing the condition
+ with a true constant. */
+ co->expr1 = gfc_get_logical_expr (gfc_default_integer_kind, &co->loc, true);
+
+ /* Hang the generated if statement into the loop body. */
+
+ loopblock = co->block->next;
+ co->block->next = c_if1;
+ c_if1->next = loopblock;
+
+ return 0;
+}
+
+/* Code callback function for converting
+ if (a) then
+ ...
+ else if (b) then
+ end if
+
+ into
+ if (a) then
+ else
+ if (b) then
+ end if
+ end if
+
+ because otherwise common function elimination would place the BLOCKs
+ into the wrong place. */
+
+static int
+convert_elseif (gfc_code **c, int *walk_subtrees ATTRIBUTE_UNUSED,
+ void *data ATTRIBUTE_UNUSED)
+{
+ gfc_code *co = *c;
+ gfc_code *c_if1, *c_if2, *else_stmt;
+
+ if (co->op != EXEC_IF)
+ return 0;
+
+ /* This loop starts out with the first ELSE statement. */
+ else_stmt = co->block->block;
+
+ while (else_stmt != NULL)
+ {
+ gfc_code *next_else;
+
+ /* If there is no condition, we're done. */
+ if (else_stmt->expr1 == NULL)
+ break;
+
+ next_else = else_stmt->block;
+
+ /* Generate the new IF statement. */
+ c_if2 = XCNEW (gfc_code);
+ c_if2->op = EXEC_IF;
+ c_if2->expr1 = else_stmt->expr1;
+ c_if2->next = else_stmt->next;
+ c_if2->loc = else_stmt->loc;
+ c_if2->block = next_else;
+
+ /* ... plus the one to chain it to. */
+ c_if1 = XCNEW (gfc_code);
+ c_if1->op = EXEC_IF;
+ c_if1->block = c_if2;
+ c_if1->loc = else_stmt->loc;
+
+ /* Insert the new IF after the ELSE. */
+ else_stmt->expr1 = NULL;
+ else_stmt->next = c_if1;
+ else_stmt->block = NULL;
+
+ else_stmt = next_else;
+ }
+ /* Don't walk subtrees. */
+ return 0;
+}
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