This patch fixes the regression by increasing the limit where we fall
back to runtime to 2**28 elements, which is the same limit where
previous releases failed. The are still bugs in the runtime
evaluation, so in many cases longer characters will still fail, so
print a warning message.
Regtested on x86_64-pc-linux-gnu, Ok for trunk?
gcc/fortran/ChangeLog:
2018-01-31 Janne Blomqvist <j...@gcc.gnu.org>
PR fortran/83705
* simplify.c (gfc_simplify_repeat): Increase limit for deferring
to runtime, print a warning message.
gcc/testsuite/ChangeLog:
2018-01-31 Janne Blomqvist <j...@gcc.gnu.org>
PR fortran/83705
* gfortran.dg/repeat_7.f90: Catch warning message.
---
gcc/fortran/simplify.c | 12 ++++++++----
gcc/testsuite/gfortran.dg/repeat_7.f90 | 2 +-
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/gcc/fortran/simplify.c b/gcc/fortran/simplify.c
index 2458956..324f858 100644
--- a/gcc/fortran/simplify.c
+++ b/gcc/fortran/simplify.c
@@ -6121,12 +6121,16 @@ gfc_simplify_repeat (gfc_expr *e, gfc_expr *n)
len = e->value.character.length;
gfc_charlen_t nlen = ncop * len;
- /* Here's a semi-arbitrary limit. If the string is longer than 32 MB
- (8 * 2**20 elements * 4 bytes (wide chars) per element) defer to
+ /* Here's a semi-arbitrary limit. If the string is longer than 1 GB
+ (2**28 elements * 4 bytes (wide chars) per element) defer to
runtime instead of consuming (unbounded) memory and CPU at
compile time. */
- if (nlen > 8388608)
- return NULL;
+ if (nlen > 268435456)
+ {
+ gfc_warning_now (0, "Evaluation of string longer than 2**28 at %L"
+ " deferred to runtime, expect bugs", &e->where);
+ return NULL;
+ }
result = gfc_get_character_expr (e->ts.kind, &e->where, NULL, nlen);
for (size_t i = 0; i < (size_t) ncop; i++)
diff --git a/gcc/testsuite/gfortran.dg/repeat_7.f90
b/gcc/testsuite/gfortran.dg/repeat_7.f90
index 82f8dbf..80a2506 100644
--- a/gcc/testsuite/gfortran.dg/repeat_7.f90
+++ b/gcc/testsuite/gfortran.dg/repeat_7.f90
@@ -4,5 +4,5 @@
! compile time.
program p
character, parameter :: z = 'z'
- print *, repeat(z, huge(1_4))
+ print *, repeat(z, huge(1_4)) ! { dg-warning "Evaluation of string" }
end program p
--
2.7.4
