similar to: [LLVMdev] LLVM Concurrency and Undef

On Sat, Sep 10, 2011 at 7:13 PM, Peter Lawrence <peterl95124 at sbcglobal.net> wrote: > > On Aug 22, 2011, at 5:29 PM, Eli Friedman wrote: > > LLVM Atomics and Concurrency guide also states the following > > "Note that speculative loads are allowed; a load which is part of a > > race returns undef, but does not have undefined behavior" > > If the

On Mon, Aug 22, 2011 at 7:27 PM, Jeffrey Yasskin <jyasskin at google.com> wrote: > On Mon, Aug 22, 2011 at 3:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>>> On

On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >> <santosh.nagarakatte at gmail.com> wrote: >>> Hi all, >>> >>> I have been trying to understand the use of undef in

On Mon, Aug 22, 2011 at 5:29 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 7:27 PM, Jeffrey Yasskin <jyasskin at google.com> wrote: >> On Mon, Aug 22, 2011 at 3:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>>> On

On Mon, Aug 22, 2011 at 3:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >>> <santosh.nagarakatte at gmail.com>

On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte > <santosh.nagarakatte at gmail.com> wrote: >> Hi all, >> >> I have been trying to understand the use of undef in both sequential >> and concurrent programs. >> >> >From the LLVM Language Reference Manual, I

On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte <santosh.nagarakatte at gmail.com> wrote: > Hi all, > > I have been trying to understand the use of undef in both sequential > and concurrent programs. > > >From the LLVM Language Reference Manual, I see the following > definition of undef. > "Undef can be used anywhere a constant is expected, and indicates

On Mon, Aug 22, 2011 at 4:20 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 6:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>>> On

On Mon, Aug 22, 2011 at 6:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >>> <santosh.nagarakatte at gmail.com>

On Mon, Aug 22, 2011 at 7:35 PM, Jeffrey Yasskin <jyasskin at google.com> wrote: > On Mon, Aug 22, 2011 at 4:20 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 6:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>>> On

Hi all, I have been trying to understand the use of undef in both sequential and concurrent programs. >From the LLVM Language Reference Manual, I see the following definition of undef. "Undef can be used anywhere a constant is expected, and indicates that the user of the value may receive an unspecified bit-pattern". LLVM Language Reference manual also demonstrates how optimizers

On Mon, Aug 22, 2011 at 8:46 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >> <santosh.nagarakatte at gmail.com> wrote: >>> Hi all, >>> >>> I have been trying to understand the use of undef in

On Tue, Aug 23, 2011 at 12:08 AM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 8:46 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >>> <santosh.nagarakatte at gmail.com>

Hi Peter, On Thu, Jun 8, 2017 at 9:41 AM, Peter Lawrence <peterl95124 at sbcglobal.net> wrote: > >> On Jun 7, 2017, at 2:23 PM, Nuno Lopes <nunoplopes at sapo.pt> wrote: >> >> Since most add/sub operations compiled from C have the nsw attribute, we cannot simply restrict movement of these instructions. > > Nuno, > I’m not saying the operations

> > Having read all of these threads, I am thoroughly convinced by the positions put forward by others. > Chandler, others have decided to let the compiler continue mis-compiling the function-inlining example, others have decided to not fix the inability to hoist a loop invariant divide out of a loop. It sounds like you haven’t even thought about these things let alone

On Mon, Aug 22, 2011 at 3:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 11:17 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 1:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 9:55 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>>> In

Sanjoy, in your blog post https://www.playingwithpointers.com/problem-with-undef.html <https://www.playingwithpointers.com/problem-with-undef.html> you describe a problem with LLVM “undef”, yet in your paper http://www.cs.utah.edu/~regehr/papers/undef-pldi17.pdf <http://www.cs.utah.edu/~regehr/papers/undef-pldi17.pdf> you do not suggest fixing this problem, even though in

On Mon, Aug 22, 2011 at 11:17 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 1:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 9:55 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>> In the definition of 'monotonic' ordering, >>> ... "If an address is written

Peter, I strongly suggest that you take a break from this email thread and careful consider the points Chandler has made about community norms and expectations before returning to this discussion. Chandler has been exceedingly patient with explaining why your behaviour is problematic and made several concrete suggestions as to productive next steps you should take. You are actively

Chandler, where we disagree is in whether the current project is moving the issue forward. It is not. It is making the compiler more complex for no additional value. The current project is not based in evidence, I have asked for any SPEC benchmark that shows performance gain by the compiler taking advantage of “undefined behavior” and no one can show that. The current project