similar to: when would I use addrspacecast?

On 16 Mar 2015, at 08:25, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > > The LangRef says this about addrspacecast: "Note that if the address > space conversion is legal then both result and operand refer to the > same memory location.". This brings forth two related questions: > > 1. what happens if you execute an "invalid" addrspacecast?

Given a pointer, does any addrspacecast affect the pointer's dereferenceablity ? For example, %pm = addrspaacecast float addrspacecast(n)* %pn to float addrspacecast(m)* %r = load float addrspace(m)* %pm In another word. the question is whether the following is true ? isDereferenceablePointer(pn) == isDereferenceablePointer(pm) [Note that the function is defined as

On 17 Mar 2015, at 20:06, Junjie Gu <jgu222 at gmail.com> wrote: >> I've just been debugging a related issue with regard to commutativity of address space casts with respect to other operations. One of the optimisers is turning an add after an address space cast into an add before the address space cast. On our architecture, this results in different bounds information being

The following combine(-enabling transformation) makes me uncomfortable:   gep(addrspacecast(gep p0) to p1)   addrspacecast(gep(gep p0)) to p1 It's applied at visitAddrSpaceCast in InstCombineCasts.cpp. Before this, I'd always assumed address spaces were very much "user domain". Datalayout even supports marking a space as "non-integral", to designate that manipulation as

Hi, I'd like to add support for addrspacecast in initializers of global variables, at least for the trivial case. The trivial case is if TargetLowering::isNoopAddrSpaceCast(SrcAS, DestAS) returns true. In this case the MCExpr for the addrspacecast is the MCExpr of its first operand. It seems hard to obtain an instance of TargetLowering in AsmPrinter::lowerConstant(). Other methods in

In the following example, for some reasons, the input pointer entering the loop was casted to generic pointer. How can the backend get rid of the addrspacecast and use local store in the loop? for.body.lr.ph: ; preds = %entry %0 = addrspacecast i32 addrspace(3)* %in to i32 addrspace(4)* br label %for.body for.body: ; preds = %for.body, %for.body.lr.ph %i.03 = phi i32 [ 0, %for.body.lr.ph ],

Hi all, the addrspacecast stuff has landed and I'm now seeing failures in our back end because clang is emitting them, they're travelling through the IR to the SelectionDAG, and there's nothing to match them. Trying to match them, I get an error from TableGen saying: Variable not defined: 'addrspacecast' If I try to set a custom OperationAction in the target lowering class

On Tue, Mar 25, 2014 at 3:21 PM, Matt Arsenault <Matthew.Arsenault at amd.com>wrote: > On 03/25/2014 02:31 PM, Jingyue Wu wrote: > > > However, we have three concerns on this: > a) I doubt this optimization is valid for all targets, because LLVM > language reference ( > http://llvm.org/docs/LangRef.html#addrspacecast-to-instruction) says > addrspacecast "can be

> What do you mean exactly by "behave differently on the other side of the cast”? Do you have a concrete example? I was hesitant to say only in that it is probably an "abuse of mechanics" and definitely playing with fire, _however_ the target I'm working on has extensive bit operations for a subset of memory, including atomic test-and-set, etc. It's convenient to be

This is a follow-up discussion on http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20140324/101899.html. The front-end change was already pushed in r204677, so we want to continue with the IR optimization. In general, we want to write an IR pass to convert generic address space usage to non-generic address space usage, because accessing the generic address space in CUDA and OpenCL is

Hi all! On x86_64, segment prefix fs: is in address space 257 and gs: in address space 256. (BTW: are there constants for these magic values?) How can I use this in IR? I want to express this assembler code in IR: mov RAX, 8; mov RAX, GS:[RAX]; ret; I tried the following: define i64 @getStackBottom(i64 %addr) { entry: %ptr = inttoptr

I'm not sure what the usual "ping time" is for llvm-dev, but may I ask if there are any updates on this? It appears that the following lines are the root cause of the reordering (https://github.com/llvm/llvm-project/blob/fdcb27105537f77c78c4473d4f7c47146ddbab69/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp#L2175): // Handle gep(bitcast x) and gep(gep x, 0, 0, 0). Value

On 2 Sep 2015, at 02:54, Joseph Tremoulet via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Reading further, I see both that addrspacecast "can be a no-op cast or a complex value modification"[2] and that bitcast "may only be [used on pointers] with the same address space"[4]. > > So I'm getting the impression that it's ok to have a model with

Thanks, David. I'd be happy to add the bindings .. is there a general way we add them? Or do you just scrub the API and make sensible judgements to the API? On Sun, Feb 1, 2015 at 1:55 PM, David Blaikie <dblaikie at gmail.com> wrote: > > > On Sun, Feb 1, 2015 at 10:58 AM, Hayden Livingston <halivingston at gmail.com > > wrote: > >> Hello, >> >> I

Are you saying the textual form of IR can change, but bitcode doesn't? I don't know what you mean by assembly syntax. Is there a changlog entry when the textual IR changes? On Sat, Mar 14, 2015 at 5:22 AM, Jeremy Lakeman <Jeremy.Lakeman at gmail.com> wrote: > Assembly syntax can and will break between versions. But bitcode should > generally be upgradeable, or a bug should

Hello, I was wondering if there is someone already working on putting the new OrcJIT APIs in the LLVM-C bindings? Also, is there a general consensus to also add C bindings when new major features are added? Hayden -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150201/061f5949/attachment.html>

Lang, aren't you going to be the major (only?) player when it comes to Orc APIs, if you're not opposed to it having them in the C bindings proper will certainly help. That's my vote, I understand it is different from the previous cases but the API surface area here is relatively small. On Mon, Sep 7, 2015 at 5:37 PM, Lang Hames <lhames at gmail.com> wrote: > Hi Jauhien, >

This is my module's dump, which is different than yours. I wonder how I can get the external thing for my function. define double @sum(double, double) { entry: call void @FooBar() %tmp = fadd double %0, %1 ret double %tmp } ; ModuleID = 'My_Module' define double @sum(double, double) { entry: call void @FooBar() %tmp = fadd double %0, %1 ret double %tmp } declare void

This is also happening when using the C++ APIs. It looks like an MCJIT and SetGC interaction. I'm lost on how to proceed further. On Tue, Mar 31, 2015 at 10:42 PM, Hayden Livingston <halivingston at gmail.com> wrote: > The erlang was a typo, I was trying things out. > > I've updated the bug with a C program, which exhibits the problem. > > To answer your question,

It is wholly self-contained. It's code that has no references to anything beyond a set of pointers passed in as arguments to the function. This piece of code doesn't do any OS work at all. It is purely calling function pointers, doing math and allocating memory. On Mon, Jul 1, 2019 at 12:57 AM Jorg Brown <jorg.brown at gmail.com> wrote: > > Qs for you: > > The code that