From e8426554e1375fec2d119ba9cc5feb263db84559 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 9 Aug 2021 13:12:08 +0200 Subject: Adjust volatile handling of the operand scanner The GIMPLE SSA operand scanner handles COMPONENT_REFs that are not marked TREE_THIS_VOLATILE but have a TREE_THIS_VOLATILE FIELD_DECL as volatile. That's inconsistent in how TREE_THIS_VOLATILE testing on GENERIC refs works which requires operand zero of component references to mirror TREE_THIS_VOLATILE to the ref so that testing TREE_THIS_VOLATILE on the outermost reference is enough to determine the volatileness. The following patch thus removes FIELD_DECL scanning from the GIMPLE SSA operand scanner, possibly leaving fewer stmts marked as gimple_has_volatile_ops. It shows we miss at least one case in the fortran frontend, though there's a suspicious amount of COMPONENT_REF creation compared to little setting of TREE_THIS_VOLATILE. This fixes the FAIL of gfortran.dg/volatile11.f90 that would otherwise occur. Visually inspecting fortran/ reveals a bunch of likely to fix cases but I don't know the constraints of 'volatile' uses in the fortran language to assess whether some of these are not necessary. 2021-08-09 Richard Biener gcc/ * tree-ssa-operands.c (operands_scanner::get_expr_operands): Do not look at COMPONENT_REF FIELD_DECLs TREE_THIS_VOLATILE to determine has_volatile_ops. gcc/fortran/ * trans-common.c (create_common): Set TREE_THIS_VOLATILE on the COMPONENT_REF if the field is volatile. --- gcc/fortran/trans-common.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'gcc/fortran/trans-common.c') diff --git a/gcc/fortran/trans-common.c b/gcc/fortran/trans-common.c index a11cf4c..7bcf18d 100644 --- a/gcc/fortran/trans-common.c +++ b/gcc/fortran/trans-common.c @@ -759,10 +759,11 @@ create_common (gfc_common_head *com, segment_info *head, bool saw_equiv) else gfc_add_decl_to_function (var_decl); - SET_DECL_VALUE_EXPR (var_decl, - fold_build3_loc (input_location, COMPONENT_REF, - TREE_TYPE (s->field), - decl, s->field, NULL_TREE)); + tree comp = build3_loc (input_location, COMPONENT_REF, + TREE_TYPE (s->field), decl, s->field, NULL_TREE); + if (TREE_THIS_VOLATILE (s->field)) + TREE_THIS_VOLATILE (comp) = 1; + SET_DECL_VALUE_EXPR (var_decl, comp); DECL_HAS_VALUE_EXPR_P (var_decl) = 1; GFC_DECL_COMMON_OR_EQUIV (var_decl) = 1; -- cgit v1.1