Re: Difficulty in implementing a GCC plugin for [[invariant]] contract functions in classes/structs without prior experience?

Hey all, I've continued to work on this and have it mostly finished The implementation is here GCC [[invariant]] plugin for Design by Contract (WIP) (github.com) I have posted the final remaining question to StackOverflow in ca

stdc_bit_ceil(3) and wrapping

Hi Joseph, I'm implementing a small part of equivalent code for shadow. I need stdc_bit_ceilul() for a random number generator limited to a range (you've seen some of this in the glibc mailing list. $ grepc -tfd shadow_random_uniform ./libmisc/random.c:76: unsigned long shadow_random_unifo

Re: stdc_bit_ceil(3) and wrapping

Hi, 30 décembre 2022 à 20:55 "Alejandro Colomar via Libc-alpha" a écrit: > > I'm implementing a small part of equivalent code for shadow. I > need > stdc_bit_ceilul() for a random number generator limited to a range (you've > seen > some of this in the glibc mailing list. > > $ grepc -tfd

Re: stdc_bit_ceil(3) and wrapping

Hi Yann, On 12/30/22 21:18, Yann Droneaud wrote: Hi, 30 décembre 2022 à 20:55 "Alejandro Colomar via Libc-alpha" a écrit: I'm implementing a small part of equivalent code for shadow. I need stdc_bit_ceilul() for a random number generator limited to a range (you've seen some of this in the

Re: stdc_bit_ceil(3) and wrapping

On Fri, 30 Dec 2022, Alejandro Colomar via Gcc wrote: > I was wondering if there was any reason to make that UB in the standard, when > unsigned wrapping has always been well-defined, and this is a case that is > likely to be implemented with some operation that wraps around, right? I It's likel

Re: stdc_bit_ceil(3) and wrapping

Hi Joseph, On 12/30/22 21:38, Joseph Myers wrote: On Fri, 30 Dec 2022, Alejandro Colomar via Gcc wrote: I was wondering if there was any reason to make that UB in the standard, when unsigned wrapping has always been well-defined, and this is a case that is likely to be implemented with some op

Re: stdc_bit_ceil(3) and wrapping

Hi Yann, On 12/30/22 21:18, Yann Droneaud wrote: 30 décembre 2022 à 20:55 "Alejandro Colomar via Libc-alpha" a écrit: I'm implementing a small part of equivalent code for shadow. I need stdc_bit_ceilul() for a random number generator limited to a range (you've seen some of this in the glibc

Re: stdc_bit_ceil(3) and wrapping

On Fri, 30 Dec 2022, Alejandro Colomar via Gcc wrote: > For the C standard, shifts have wrap around semantics for unsigned types: Only if the shift count is nonnegative and strictly less than the width of the type. This is about shifting by an amount equal to the width of the type, which has u

Re: stdc_bit_ceil(3) and wrapping

On 12/30/22 21:56, Joseph Myers wrote: On Fri, 30 Dec 2022, Alejandro Colomar via Gcc wrote: For the C standard, shifts have wrap around semantics for unsigned types: Only if the shift count is nonnegative and strictly less than the width of the type. This is about shifting by an amount equa

Re: stdc_bit_ceil(3) and wrapping

On 12/30/22 22:01, Alejandro Colomar wrote: On 12/30/22 21:56, Joseph Myers wrote: On Fri, 30 Dec 2022, Alejandro Colomar via Gcc wrote: For the C standard, shifts have wrap around semantics for unsigned types: Only if the shift count is nonnegative and strictly less than the width of the ty

Re: stdc_bit_ceil(3) and wrapping

Hi Yann, On 12/30/22 21:33, Alejandro Colomar wrote: On 12/30/22 21:18, Yann Droneaud wrote: What's wrong with the following ? [...] unsigned long max = upper_bound - 1; unsigned long mask = ULONG_MAX >> __builtin_clzl(max); I hate coding these magic operations out of a funct

gcc-11-20221230 is now available

Snapshot gcc-11-20221230 is now available on https://gcc.gnu.org/pub/gcc/snapshots/11-20221230/ and on various mirrors, see http://gcc.gnu.org/mirrors.html for details. This snapshot has been generated from the GCC 11 git branch with the following options: git://gcc.gnu.org/git/gcc.git branch