| Message ID | 53FE46CB.6030505@net-b.de |
|---|---|
| State | New |
| Headers | show |
Tobias Burnus wrote: > { > + symbol_attribute attr1, attr2; > gfc_typespec *ts1 = &expr1->symtree->n.sym->ts; > - gfc_typespec *ts2 = &expr2->symtree->n.sym->ts; > + gfc_typespec *ts2 = &expr2->symtree->n.sym->ts; [Ignore the "ts2"-line change: I have accidentally added a spurious " " in column 1, and missed it when sending the patch out.] Tobias
Dear Tobias, Given Dominques news that this fixes a golden oldie that drove me to madness and PR60593 - OK for trunk, 4.8 and 4.9 Many thanks for the patch Paul On 27 August 2014 22:59, Tobias Burnus <burnus@net-b.de> wrote: > The current gfc_check_dependency check always looked at the pointer > attribute - and assumed the worst, if either the LHS or the RHS was true. > > Thus, it claimed that "a" and "b" alias for the following definition: > integer, pointer :: p; integer :: a. However, as "a" has no target (or > pointer) attribute, that's not possible. Additionally, "class(t) :: a" has > internally the "pointer" attribute (but CLASS_DATA(sym)->attr.class_pointer > == 0), however, in the Fortran sense, "a" is not a pointer and cannot alias. > > I do not have a good example for the test case, except for a similar one as > above using "a[i] = p" and looking at the dump; but that requires patch 3/3 > of this series. > > Build and regtested on x86-64-gnu-linux. (I do get a failure for > gfortran.dg/graphite/pr42393.f90, but only with -O1 -fgraphite-identity and > also without the patch.) > > OK for the trunk? > > Tobias
2014-08-27 Tobias Burnus <burnus@net-b.de> PR fortran/62278 * dependency.c (gfc_check_dependency): Allow for optimizations in the pointer-alias check. diff --git a/gcc/fortran/dependency.c b/gcc/fortran/dependency.c index c18482a..1cdd141 100644 --- a/gcc/fortran/dependency.c +++ b/gcc/fortran/dependency.c @@ -1269,8 +1269,9 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical) /* The interesting cases are when the symbols don't match. */ if (expr1->symtree->n.sym != expr2->symtree->n.sym) { + symbol_attribute attr1, attr2; gfc_typespec *ts1 = &expr1->symtree->n.sym->ts; - gfc_typespec *ts2 = &expr2->symtree->n.sym->ts; + gfc_typespec *ts2 = &expr2->symtree->n.sym->ts; /* Return 1 if expr1 and expr2 are equivalenced arrays. */ if (gfc_are_equivalenced_arrays (expr1, expr2)) @@ -1284,9 +1285,13 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical) return 0; } - /* If either variable is a pointer, assume the worst. */ - /* TODO: -fassume-no-pointer-aliasing */ - if (gfc_is_data_pointer (expr1) || gfc_is_data_pointer (expr2)) + /* We have to also include target-target as ptr%comp is not a + pointer but it still alias with "dt%comp" for "ptr => dt". As + subcomponents and array access to pointers retains the target + attribute, that's sufficient. */ + attr1 = gfc_expr_attr (expr1); + attr2 = gfc_expr_attr (expr2); + if ((attr1.pointer || attr1.target) && (attr2.pointer || attr2.target)) { if (check_data_pointer_types (expr1, expr2) && check_data_pointer_types (expr2, expr1))