Steve Kargl <s...@troutmask.apl.washington.edu> writes: > On Sat, Feb 01, 2025 at 09:49:17PM +0100, Harald Anlauf wrote: >> Am 01.02.25 um 21:03 schrieb Steve Kargl: >> > On Sat, Feb 01, 2025 at 07:25:51PM +0100, Harald Anlauf wrote: >> > > >> > > the attached patch downgrades different constant character lengths in an >> > > array constructor from a GNU to a legacy extension, so that users get a >> > > warning with -std=gnu. We continue to generate an error when standard >> > > conformance is requested. >> > > >> > > Regtested on x86_64-pc-linux-gnu (found one testcase where this >> > > triggered... :) >> > > >> > > OK for mainline? >> > > >> > >> > My vote is 'no'. >> > >> > This is either a GNU extension or an error. It is certainly >> > not a legacy issue as array constructors simple cannot appear >> > old moldy *legacy* codes. >> >> legacy /= moldy. >> >> My intention is to downgrade existing, potentially dangerous >> GNU extensions (like this one) carefully to "legacy", but not >> with an axe. >> >> > I would be in favor of making it a hard error. If you believe >> > gfortan must be able to compile invalid source, then add an option >> > such as -fallow-invalid-scalar-character-entities-in-array-constructor. >> >> I don't see why we shall scare users by making code that is currently >> accepted silently, because it is a GNU extension, suddenly to a hard >> error. >> >> So why must we be so tough? >> > > Because -std=legacy allows a whole bunch of garbage. > > Instead of fixing broken code, a user will slap -std=legacy > in a Makefile and move on. Then years from now, you'll see > -std=legacy in a whole bunch of Makefiles whether it is needed > or not. See -maligned-double and -fallow-argument-mismatch as > poster children.
I agree that this is what will happen. But for people running benchmarks, it's kind-of (kind-of) a feature. Benchmarks tend to include relatively old code by the time that they're released, and benchmarks continue to be relevant (or at least widely tested) after they're out of maintenance. So it has been really useful to have -std=legacy accept old, dangerous code, since it means that we can continue to test old benchmarks with newer compilers. Improving the benchmark source to avoid the dangerous constructs would invalidate the test and make it harder to compare with historical results. > Again, just my $0.02. Same here, just wanted to raise the benchmark use case. Thanks, Richard
