From 9da696478832bb3fe5ac25542ad9226ce3235368 Mon Sep 17 00:00:00 2001 From: Mikael Morin Date: Tue, 26 Apr 2022 13:05:32 +0200 Subject: [PATCH v2] fortran: Avoid infinite self-recursion [PR105381] Dummy array decls are local decls different from the argument decl accessible through GFC_DECL_SAVED_DESCRIPTOR. If the argument decl has a DECL_LANG_SPECIFIC set, it is copied over to the local decl at the time the latter is created, so that the DECL_LANG_SPECIFIC object is shared between local dummy decl and argument decl, and thus the GFC_DECL_SAVED_DESCRIPTOR of the argument decl is the argument decl itself. The r12-8230-g7964ab6c364c410c34efe7ca2eba797d36525349 change introduced the non_negative_strides_array_p predicate which recurses through GFC_DECL_SAVED_DESCRIPTOR to avoid seeing dummy decls as purely local decls. As the GFC_DECL_SAVED_DESCRIPTOR of the argument decl is itself, this can cause infinite recursion. This change adds a check to avoid infinite recursion. PR fortran/102043 PR fortran/105381 gcc/fortran/ChangeLog: * trans-array.cc (non_negative_strides_array_p): Inline variable orig_decl and merge nested if conditions. Add condition to not recurse if the next argument is the same as the current. gcc/testsuite/ChangeLog: * gfortran.dg/character_array_dummy_1.f90: New test. --- gcc/fortran/trans-array.cc | 7 ++++--- .../gfortran.dg/character_array_dummy_1.f90 | 21 +++++++++++++++++++ 2 files changed, 25 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/character_array_dummy_1.f90 diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc index e4b6270ccf8..05134952db4 100644 --- a/gcc/fortran/trans-array.cc +++ b/gcc/fortran/trans-array.cc @@ -3696,9 +3696,10 @@ non_negative_strides_array_p (tree expr) /* If the array was originally a dummy with a descriptor, strides can be negative. */ if (DECL_P (expr) - && DECL_LANG_SPECIFIC (expr)) - if (tree orig_decl = GFC_DECL_SAVED_DESCRIPTOR (expr)) - return non_negative_strides_array_p (orig_decl); + && DECL_LANG_SPECIFIC (expr) + && GFC_DECL_SAVED_DESCRIPTOR (expr) + && GFC_DECL_SAVED_DESCRIPTOR (expr) != expr) + return non_negative_strides_array_p (GFC_DECL_SAVED_DESCRIPTOR (expr)); return true; } diff --git a/gcc/testsuite/gfortran.dg/character_array_dummy_1.f90 b/gcc/testsuite/gfortran.dg/character_array_dummy_1.f90 new file mode 100644 index 00000000000..da5ed636f4f --- /dev/null +++ b/gcc/testsuite/gfortran.dg/character_array_dummy_1.f90 @@ -0,0 +1,21 @@ +! { dg-do compile } +! +! PR fortran/105381 +! Infinite recursion with array references of character dummy arguments. +! +! Contributed by Harald Anlauf + +MODULE m + implicit none + integer, parameter :: ncrit = 8 + integer, parameter :: nterm = 7 +contains + + subroutine new_thin_rule (rule1) + character(*),intent(in) ,optional :: rule1(ncrit) + character(len=8) :: rules (ncrit,nterm) + rules = '' + if (present (rule1)) rules(:,1) = rule1 ! <-- compile time hog + end subroutine new_thin_rule + +end module m -- 2.35.1