Re: semantics of uninitialized values in GIMPLE

2023-07-20 Thread Krister Walfridsson via Gcc
On Tue, 11 Jul 2023, Krister Walfridsson wrote: On Tue, 11 Jul 2023, Richard Biener wrote: I'll update my implementation, and will come back with a more detailed proposal in a few weeks when I have tried some more things. Thanks! I've also taken the opportunity given by your work at the recen

Re: semantics of uninitialized values in GIMPLE

2023-07-11 Thread Krister Walfridsson via Gcc
On Tue, 11 Jul 2023, Richard Biener wrote: I'll update my implementation, and will come back with a more detailed proposal in a few weeks when I have tried some more things. Thanks! I've also taken the opportunity given by your work at the recent bugs to propose a talk at this years GNU Cauld

Re: semantics of uninitialized values in GIMPLE

2023-07-11 Thread Richard Biener via Gcc
On Tue, Jul 11, 2023 at 10:29 AM Krister Walfridsson wrote: > > On Tue, 11 Jul 2023, Richard Biener wrote: > > >> With "plain copies", do you mean treating it as it is always defined? That > >> would prevent optimizations such as transforming > >> > >>int t; > >>if (1) > >> t = *p; >

Re: semantics of uninitialized values in GIMPLE

2023-07-11 Thread Krister Walfridsson via Gcc
On Tue, 11 Jul 2023, Richard Biener wrote: With "plain copies", do you mean treating it as it is always defined? That would prevent optimizations such as transforming int t; if (1) t = *p; else t = 0; return t + 1; to the equivalent of return *p + 1; because the latt

Re: semantics of uninitialized values in GIMPLE

2023-07-11 Thread Richard Biener via Gcc
On Tue, Jul 11, 2023 at 12:56 AM Krister Walfridsson wrote: > > On Fri, 7 Jul 2023, Richard Biener wrote: > > >> I have implemented support for uninitialized memory in my translation > >> validator. But I am not sure how well this corresponds to the GIMPLE > >> semantics, so I have some questions.

Re: semantics of uninitialized values in GIMPLE

2023-07-10 Thread Krister Walfridsson via Gcc
On Fri, 7 Jul 2023, Richard Biener wrote: I have implemented support for uninitialized memory in my translation validator. But I am not sure how well this corresponds to the GIMPLE semantics, so I have some questions... My implementation tracks uninitialized bits. Use of uninitialized bits is i

Re: semantics of uninitialized values in GIMPLE

2023-07-06 Thread Richard Biener via Gcc
On Fri, Jul 7, 2023 at 1:23 AM Krister Walfridsson via Gcc wrote: > > I have implemented support for uninitialized memory in my translation > validator. But I am not sure how well this corresponds to the GIMPLE > semantics, so I have some questions... > > My implementation tracks uninitialized bit

semantics of uninitialized values in GIMPLE

2023-07-06 Thread Krister Walfridsson via Gcc
I have implemented support for uninitialized memory in my translation validator. But I am not sure how well this corresponds to the GIMPLE semantics, so I have some questions... My implementation tracks uninitialized bits. Use of uninitialized bits is in general treated as UB (for example, `x