Re: [PATCH 1/2] alloca-opt-tests: add a ‘volatile’
On 2024-05-17 02:48, Bruno Haible wrote: -flto was buggy for a long time. Is whole-program optimization working fine for you? If so, which compiler version, binutils version, and compiler options can you recommend? No, I merely found that problem by program inspection. Like you, I've had problems with -flto. The longer story is that my coreutils build was using GCC 14's new -Wmissing-variable-declarations behavior, which is a mistake for tests. While noticing the mistake I looked briefly at the complaints. This was an early test that -Wmissing-variable-declarations complained about and when I looked at the complaint I happened to notice the potential problem with whole-program optimization, something that has nothing to do with -Wmissing-variable-declarations. In my weaker moments I sometimes think we should declare every test-case variable volatile, along the lines of the "volatile-by-default" approach for Java. See: Liu L, Millstein T, Musuvathi M. Safe-by-default concurrency for modern programming languages. ACM TOPLAS. 2021;43(3):10. https://doi.org/10.1145/3462206
Re: [PATCH 1/2] alloca-opt-tests: add a ‘volatile’
Hi Paul, > Now volatile, to foil whole-program optimization. -flto was buggy for a long time. Is whole-program optimization working fine for you? If so, which compiler version, binutils version, and compiler options can you recommend? Bruno
[PATCH 1/2] alloca-opt-tests: add a ‘volatile’
* tests/test-alloca-opt.c (func) [HAVE_ALLOCA]: Now volatile, to foil whole-program optimization. --- ChangeLog | 6 ++ tests/test-alloca-opt.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index 6436ddfb81..a8ed30c4ae 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2024-05-16 Paul Eggert + + alloca-opt-tests: add a ‘volatile’ + * tests/test-alloca-opt.c (func) [HAVE_ALLOCA]: + Now volatile, to foil whole-program optimization. + 2024-05-16 Collin Funk byteswap tests: Strengthen tests. diff --git a/tests/test-alloca-opt.c b/tests/test-alloca-opt.c index 3f20779c9e..b22921758e 100644 --- a/tests/test-alloca-opt.c +++ b/tests/test-alloca-opt.c @@ -29,7 +29,7 @@ do_allocation (int n) (void) ptr; } -void (*func) (int) = do_allocation; +void (*volatile func) (int) = do_allocation; #endif -- 2.45.0
