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Hi, I am investigating a difference in code generation between release and assert builds of llvm. The culprit is IndVarSimplify that comes up with different behavior on the same input: in the assertion build, it does do an extra 'INDVARS: Rewriting loop exit condition' After digging around, it seems that following change is the culprit: ----- Author: Philip Reames <listmail at

I'd missed the fact that j wasn't just being decremented. This isn't as easy as I said. Philip On 03/03/2016 02:36 PM, Philip Reames via llvm-dev wrote: > SCEV should be able to easily prove that j is positive here. I'm not > sure where the right place to use that information would be in this > case. Sanjoy, can you comment? > > Philip > > On 03/03/2016

With floating point, won't you need to model a partial order for the end points? I thought there were pairs of floating point values which are incomparable. Not sure if partial order is the right abstraction, but I'm pretty sure a total order isn't. This may make implementing the range comparisons (which are themselves partially ordered) a bit tricky... Philip (Who knows just

Hi Jimmy, It's good to know that the problem is not specific to the case I ran into. May be you can provide your example as well, since Philip seems to be interested in some specific examples. If the assertion in getAddrExpr is deemed necessary, then I think a condition check would be the next best solution as it helps client code guard against such cases and make alternative arrangements to

Thanks for sharing the known problem. I think to solve the problem properly, we need to fully understand why that assumption about dominance is there and the implications of removing it. It would be good if you could be more specific about your idea of nullptr or SCEV_unknown (eg which function would return those values and when), but returning nullptr from getAddExpr or getSCEVAtScope may be

> Checks against 1.0 are also common. Why not just add a FP range class, like our constant range, and go from there? That's certainly another way to go. My worry is that a more complicated lattice gets us deeper into rounding-mode issues and considerably more work for smaller gain. I like the idea of creating an FPRange class. We could start with a simple one and extend it as experience

Just to be clear, you mean the release notes for 3.7 not 3.6 right? On 03/04/2015 02:15 PM, Hans Wennborg wrote: > This is great. Can you add it to the release notes? > > On Fri, Feb 27, 2015 at 3:34 PM, Philip Reames > <listmail at philipreames.com> wrote: >> The first version of this document is now live: >> http://llvm.org/docs/Frontend/PerformanceTips.html

> On Jan 22, 2020, at 19:49, Philip Reames <listmail at philipreames.com> wrote: > > In short, I hit a major stumbling block. I hadn't account for the fact that some atomic stores dependent on element type (float vs int for instance) for legality. I think this qualifies as a target/infrastructure bug. It should always be legal to cast the FP atomic load/store to integer. This

SGTM On 02/17/2018 03:52 PM, Nuno Lopes wrote: > I can step in, if that's ok with you. > Nuno > > -----Original Message----- From: Philip Reames > Sent: Saturday, February 17, 2018 1:04 AM > To: Davide Italiano ; Nuno Lopes > Cc: llvm-dev > Subject: Re: [llvm-dev] Missing attribute inference cases > > Sure, but is anyone willing to mentor?  I don't have

Hey Scott, There has been quite a lot of research on capture tracking (aka escape analysis) for Java and other dynamic languages. See e.g.: https://wiki.openjdk.java.net/display/HotSpot/EscapeAnalysis http://docs.oracle.com/javase/7/docs/technotes/guides/vm/performance-enhancements-7.html http://dl.acm.org/citation.cfm?doid=320384.320386 Nuno -----Original Message----- From: Scott Egerton via

Sure, but is anyone willing to mentor?  I don't have time.  I can advise, but only infrequently. Philip On 02/16/2018 03:47 PM, Davide Italiano wrote: > Yes, I agree with you this sounds like a great GSoC. > > On Fri, Feb 16, 2018 at 3:42 PM, Nuno Lopes via llvm-dev > <llvm-dev at lists.llvm.org> wrote: >> Maybe we could list some of these as a GSoC project?

Per my previous email, I have just signed off on Artur's original patch. Philip On 03/02/2016 11:21 AM, Philip Reames via llvm-dev wrote: > Elena, > > I'd like to propose that we move forward withArtur's original patch > <http://reviews.llvm.org/D17270> and separate the discussion of how we > might change our intrinsic naming scheme. Artur's patch is

Yes, the modeling of floating-point is trickier. The wrap-around trick used by ConstantRange seems less applicable, and there are the unordered NaNs. Though in all cases, the key abstraction is a lattice of values, so an instance of FPRange should be thought of as a point on a lattice, not an interval. The lattice needs to be complicated enough the cover the cases of interest, but not so

On 02/24/2014 11:27 AM, Andrew Trick wrote: > > On Feb 24, 2014, at 11:17 AM, Philip Reames <listmail at philipreames.com > <mailto:listmail at philipreames.com>> wrote: > >> >> On 02/24/2014 12:45 AM, Andrew Trick wrote: >>> >>> On Feb 21, 2014, at 10:37 AM, Philip Reames >>> <listmail at philipreames.com <mailto:listmail at

I can step in, if that's ok with you. Nuno -----Original Message----- From: Philip Reames Sent: Saturday, February 17, 2018 1:04 AM To: Davide Italiano ; Nuno Lopes Cc: llvm-dev Subject: Re: [llvm-dev] Missing attribute inference cases Sure, but is anyone willing to mentor? I don't have time. I can advise, but only infrequently. Philip On 02/16/2018 03:47 PM, Davide Italiano wrote:

I really hate to dip my toe in here, because it will only reveal my total ignorance, but…. Do the "usual rules around addrspacecast" say when different address spaces can alias? I remember somebody using address spaces to represent something like special off-to-the-side device memory, which obviously could never alias main memory, whereas other uses like the 32/64-bit thing will

> On Mar 1, 2015, at 7:53 AM, Björn Steinbrink <bsteinbr at gmail.com> wrote: > > On 2015.02.28 18:17:27 -0800, Philip Reames wrote: >>> On Feb 28, 2015, at 3:01 PM, Björn Steinbrink <bsteinbr at gmail.com> wrote: >>> 2015-02-28 23:50 GMT+01:00 Philip Reames <listmail at philipreames.com>: >>>>>> On Feb 28, 2015, at 2:30 PM, Björn

> On Aug 17, 2016, at 2:08 PM, Zhuravlyov, Konstantin <Konstantin.Zhuravlyov at amd.com> wrote: > > >Why not going with a metadata attachment directly and kill the "singlethread" keyword? Something like: > >Something like: > > cmpxchg i32* %addr, i32 42, i32 0 monotonic monotonic, 3, !memory.scope{!42} > > cmpxchg i32* %addr, i32 42, i32 0 monotonic

This probably needs broader discussion. We have an existing naming mechanism for polymorphic intrinsics; Elena is proposing a new one to avoid making the names for various load/store intrinsics particularly ugly. My personal take: 1) I like the cleaner naming scheme. 2) I'm not sure the additional complexity is worth it. (Not specific to the particular implementation proposed here.) 3) I

On Fri, Jul 31, 2015 at 3:53 PM, Philip Reames <listmail at philipreames.com> wrote: > > Quoting from the google doc: "If we don’t know definition of some > function, we assume that it will not call @llvm.invariant.group.barrier(). > " > This part really really bugs me. We generally try to assume minimal > knowledge of external functions (i.e. they can do