On Mon, Feb 27, 2023 at 09:54:38PM +0100, Harald Anlauf via Fortran wrote: > > as found by the reporter, the result of the intrinsic IBITS > differed from other compilers (e.g. Intel, NAG) for the corner > case that the LEN argument was equal to BIT_SIZE(I), which is > explicitly allowed by the standard. > > We actually had an inconsistency for this case between > code generated by the frontend and compile-time simplified > expressions. > > The reporter noticed that this is related to a restriction in > gcc that requires that shift widths shall be smaller than the > bit sizes, and we already special case this for ISHFT. > It makes sense to use the same special casing for IBITS. > > Attached patch fixes this and regtests on x86_64-pc-linux-gnu. > > OK for mainline?
Yes. Good catch on comparison with simplification, which I failed to consider last night. > This issue has been there for ages. Shall this be backported > or left in release branches as is? As always, backporting is up to you and your bandwidth. Bring the the run-time result and simplification into agreement suggests that a back port is a good thing. -- Steve
