search for: int_max

On Sun, Feb 8, 2015 at 8:38 AM, Hal Finkel <hfinkel at anl.gov> wrote: > > Currently, we might replace: > %cmp = icmp sgt i32 undef, INT_MAX -> i1 false > > According to this proposal, we could replace: > %cmp = icmp sgt i32 undef, INT_MAX -> i1 undef > > While replacing it with false is still allowed, so is replacing it with > true. I'm not sure this makes sense. I think your example is a compelling argum...

...ds like a fairly > straight forward extension to the LazyValueInfo analysis. In > particular, take a look at getValueFromICmpCondition. I'd be happy to > help review a patch here once you've got something working. > > The basic idea would be that (X s<Y ) implies X s< INT_MAX since Y must > be INT_MAX or smaller and X is less than that. We can tell this without > needing to know anything about Y. Looks like a good idea, but I'm not sure how LazyValueInfo's interface would support this case. Did you mean synthesizing the INT_MAX constant and then checki...

One way around this is to say that there are some special instructions, icmp, sext and zext which produce a value solely composed of poison bits if any of their input bits is poison. So `<poison> icmp X` is poison for any value of X, including INT_MAX. This is one way poison could be fundamentally different from undef. -- Sanjoy On Thu, Jan 29, 2015 at 8:05 PM, Matthias Braun <matze at braunis.de> wrote: > Having though about this some more I think optimizing > > (x+1 > x) <=> true > > and at the same time modelin...

Hi, I don't see any way to view the details of a certificate once it is generated. Having such a capability would be very handy for debugging purposes to check what constraints, principals, and validity interval are associated with a given cert. -- Iain Morgan

On Sun, Feb 8, 2015 at 10:02 AM, Hal Finkel <hfinkel at anl.gov> wrote: > > When you say, "we'd like to", I'm assuming your justification for this is > so that we can model poison using these undef semantics. Is that correct? > Yes, but I also think 'icmp sgt i32 undef, %a -> i1 undef' is a pretty reasonable transform by itself. Well-defined programs

But (Poison > INT_MAX) <=> poison contradicts (X > INT_MAX) <=> false and I don't think you want to abandon the second rule just because x might be poison. - Matthias > On Jan 29, 2015, at 9:43 PM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > > One way around this is to s...

On Thu, Jan 29, 2015 at 10:01 PM, Matthias Braun <matze at braunis.de> wrote: > But > (Poison > INT_MAX) <=> poison > contradicts > (X > INT_MAX) <=> false > > and I don't think you want to abandon the second rule just because x might be poison. Maybe we could define poison in such a way that it is safe to pretend it "is" false, as per our convenience. In th...

...0, Jason Wang wrote: > > > @@ -556,10 +667,14 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) > > > size_t len, total_len = 0; > > > int err; > > > int sent_pkts = 0; > > > + bool bulking = (sock->sk->sk_sndbuf == INT_MAX); > > What does bulking mean? > > The name is misleading, it means whether we can do batching. For simplicity, > I disable batching is sndbuf is not INT_MAX. But what does batching have to do with sndbuf? > > > for (;;) { > > > bool busyloop_intr = false;...

...limitation, see ScalarEvolution.cpp:5568. > > The fundamental problem is that len in your example could be (unsigned) > -1, -2 or -3, in which case your loop is infinite. > Unless I'm missing something, if len is -1 (or otherwise less than 0) the loop has 0 trip count. Did you mean INT_MAX-1, INT_MAX-2 etc? In this case, I believe, the behavior is undefined, because adds are marked with "nsw". Eugene -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130822/74d2c0f9/attachment.html>

...mention a default 2GB limit, especially not on win64; - man page of memory.limit and rw-FAQ Q2.9 say that you can set the limit via --max-mem-size or R_MAX_MEM_SIZE env var: both work only in standalone R (Rf_initEmbeddedR ignores them); - R\src\gnuwin32\system.c defines R_size_t R_max_memory = INT_MAX; which is the reason of the 2GB default limit on embedded R; however INT_MAX is not the maximum integer value of an R_size_t variable either on win32 nor on win64; - line 879 of the same system.c source says: "/* set defaults for R_max_memory. This is set here so that embedded applications g...

...cannot prove (2) then we did something wrong in specifying step (1). -- Sanjoy On Thu, Jan 29, 2015 at 10:05 PM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > On Thu, Jan 29, 2015 at 10:01 PM, Matthias Braun <matze at braunis.de> wrote: >> But >> (Poison > INT_MAX) <=> poison >> contradicts >> (X > INT_MAX) <=> false >> >> and I don't think you want to abandon the second rule just because x might be poison. > > Maybe we could define poison in such a way that it is safe to pretend > it "is" false,...

The problem seems that ":" always coerces to integer, but should not.. 9.9:12 ## R: [1] 9 10 11 ## S-plus 3.4: [1] 9.9 10.9 11.9 ## and many more examples.... -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or

By my reading, R has a hard limit on INT_MAX bytes for vector allocations. On the sparcv9 architecture, INT_MAX is a 32 bit quantity, even though pointers can be 64 bits. Has any thought been given to use of > 2GB of virtual memory on systems like this? -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-he...

...n.cpp:5568. >> >> The fundamental problem is that len in your example could be (unsigned) >> -1, -2 or -3, in which case your loop is infinite. >> > > Unless I'm missing something, if len is -1 (or otherwise less than 0) the > loop has 0 trip count. Did you mean INT_MAX-1, INT_MAX-2 etc? In this case, > I believe, the behavior is undefined, because adds are marked with "nsw". > Doh, 's' was unsigned, 'i' was signed. My mistake. Regardless, this part of SCEV isn't looking for NSW bits yet and consequently is optimizing as-if th...

Having though about this some more I think optimizing (x+1 > x) <=> true and at the same time modeling undefined behavior as a posion value is impossible. This is because we also want the following rule: (x > INT_MAX) <=> false Now if poison is a value, then the second replacement tells us (poison > INT_MAX) == false which contradicts the first rule. The only way out of this while still allowing (x+1>x)<=>true I can see at the moment is defining that add nsw does produce actual undefined b...

...uld be to change the type of "size" to "intmax_t", from "int64_t". > > That way, the assignment will be safe even theoretically, *and* the > > overflow check at the bottom of the function (with the division & > > comparison of the quotient against INT_MAX) will work just the same. > > I'm always very unsure how this all works. In particular I seem to > recall that intmax_t is no longer really the maximum possible int > (because of int128) and so it's always 64 bit on platforms we care > about. Can Eric comment? intmax_t wa...

...ith parent_dir->counter++ and that weird setting of f_pos to 2^31-1. So after enough creates (and deletes :)) in a directory we end up with an entry item whose key is past that value. f_pos gets rewound instead of being set to that magical EOF. readdir() gets stuck returning the entries after INT_MAX over and over (just one in this strace): getdents(3, {{d_ino=257, d_off=2147483647, d_reclen=32, d_name="file-54"}}, 32768) = 32 getdents(3, {{d_ino=257, d_off=2147483647, d_reclen=32, d_name="file-54"}}, 32768) = 32 It took around 10 hours on a workstationy box over here to r...

> I've been discussing a model with David that might steer poison back towards > something that simply supports algebraic simplification. If we have a math > operation that cannot wrap, then it notionally produces as many bits of > undef as the operation could possibly produce. For example, "add nsw i8" can > produce an i9 undef, and "mul nsw i8" can produce

Hi everyone, I posted some questions related to implementing inference of nsw/nuw flags based on known icmp results to Bug 30428 ( https://llvm.org/bugs/show_bug.cgi?id=30428 ) and it was recommended that I engage a wider audience by coming here. The minimal context is the following, please see the bug report for more detail: > 1. If (X s< Y), then both X + 1 and Y - 1 are nsw. > 2.

Hi Pete, > Or do you mean that the result of an add may not even be defined? In that case would reading it be considered UB in the case where the overflow bit was set? Yeah, this is the case I'm worried about: that for example sadd.with.overflow(INT_MAX, 1) might be designed to return { poison, true } instead of giving a useful result in the first element of the struct. John