similar to: llvm-ir: TBAA and struct copies

Hi Ivan, The code that we have is indeed different from what the 'standard llvm' expects. Let me explain: in our version we came into this situation in two steps: 1) I added support for 'special types' that map directly to types supported by hardware. These types are represented by a struct containing a single iXXX member, providing the necessary bits of the type, and at the

So I've been narrowing down a very fun issue in our Burst compiler stack with respect to noalias support, and I've managed to basically boil this down to the following failure (see https://godbolt.org/z/-mdjPV): int called(int* __restrict__ a, int* b, int* c) { return *a + *b + *c; } int foo(int * x, int * y) { return *x + *y + called(x, x, y); } int bar(int * x, int * y) { return

Thanks, Jeroen, that really helps. A follow-up question, if you don't mind. What if we have code somewhat similar to your example in assign3() but it's in C++ and the pointer derived from x is stored in a class member field: class S { public: S(int *d): data(d) {} int *getData() { return data; } private: int *__restrict__ data; }; void assign4(int *pA, long N) { int

We recently found an issue when using the full restrict implementation developed by Jeroen; it surfaces when compiling an obscure combination of std::valarray and std::indirect_array but I don't want to bore you with all the details. What it boils down to is this basic question about restrict: Given one restrict pointer based on another, should they never alias? As far as I understand the

On 06/28/2018 10:59 AM, Hal Finkel wrote: > Hi, Jeroen, > > We should move these conversations to llvm-dev so that they don't get > missed and others can contribute. Can I cc the list? [+llvm-dev] - Jeroen consented. > > Doing this will mean that the logic for when to remove dead llvm.noalias > intrinsics will become more complicated. That might be worthwhile. So >

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

Johannes, Thanks, I have been following along some of the thread(s) and the phab reviews. The scope of this work is more encompassing than our current needs and I've looked at trying to carve a piece out. It's not clear to me what purpose the llvm.noalias intrinsic serves right now. Also, if a mem instruction has !noalias metadata, then it should not be aliased, but I must be missing

At a high level, EarlyCSE should be intersecting the metadata of instructions that it combines. If it doesn't, and also doesn't drop the metadata, that seems like a bug, regardless of anything else. On 1/22/20 9:30 AM, Jeroen Dobbelaere wrote: Hi Neil, Hall, - as far as 'C' is concerned, this is input code is valid, as the pointers are not used to modify objects. - as far as

Hi Jeroen, Sorry, I missed that. I tried the patch, and this program: #include <stdint.h> #define __remote __attribute__((address_space(1))) __remote int* A; __remote int* B; void vec_add(__remote int* __restrict a, __remote int* __restrict b, int n) { #pragma unroll 4 for(int i=0; i<n; ++i) { a[i] += b[i]; } } int main(int argc, char** argv) {

Hi, I'm trying to abstract some special pointers with a class, like in the example program below: 1 #define __remote __attribute__((address_space(1))) 2 #include <stdint.h> 3 4 __remote int* A; 5 __remote int* B; 6 7 class RemotePtr { 8 private: 9 __remote int* __restrict a; 10 11 public: 12 RemotePtr(__remote int* a) : a(a) {} 13 14 __remote

Hi Jeroen, That's great! I was trying to use the patch, what's the latest version of the project we could apply it on? Hi Neil, That seems like what I can do as well! Do you happen to have some examples lying around? Maybe a pointer to the planned presentation, if that's okay? Thank you, Bandhav On Mon, Jun 22, 2020 at 1:55 AM Neil Henning <neil.henning at unity3d.com>

I'm having an issue where SROA will throw away no-alias information on some loads after inlining, because the loads are derived from a store to an alloca which can be removed after inlining. The pointers that were originally stored into the alloca do *not *have any aliasing information - the only context that allowed me to assert aliasing was that the inlined-function guaranteed it to be so.

Hi Hal, On Fri, Apr 4, 2014 at 12:44 AM, Hal Finkel <hfinkel at anl.gov> wrote: > ----- Original Message ----- > > From: "Jeroen Dobbelaere" <jeroen.dobbelaere at gmail.com> > [... ] > > I am trying to get llvm working for an architecture that has 64bit > > registers, but 32bit addresses. > > Because of that, I want the pointers to also be

Hi Hal, On Fri, Apr 4, 2014 at 1:22 PM, Hal Finkel <hfinkel at anl.gov> wrote: > [..] > Agreed; but what does your *ISelLowering::getPointerTy() function look > like? Did you override the default implementation? I wonder if returning > MVT::i64 from this function will make things work for you. > > -Hal > > I actually missed implementing this one. But, depending

Hi, We, IBM XL Fortran compiler team, is interested in representing Fortran alias information in LLVM IR. We use the XL Fortran frontend to emit LLVM IR that includes alias information to feed to the LLVM in order to create object files. For the Fortran alias representation in LLVM IR, we considered both TBAA and ScopeAlias/NoAlias metadata approaches, we think that the ScopeAlias/NoAlias

On 08/23/2017 12:44 PM, David Chisnall wrote: > On 23 Aug 2017, at 18:21, Hal Finkel via llvm-dev <llvm-dev at lists.llvm.org> wrote: >> >> On 08/23/2017 12:06 PM, Krzysztof Parzyszek via llvm-dev wrote: >>> On 8/23/2017 11:58 AM, Hal Finkel via llvm-dev wrote: >>>> If we want to go down that route, I can certainly imagine a feasible

> From: Eric Christopher > Subject: Re: [LLVMdev] How to associate extra comments to a > MachineInstruction ? > > Should be spelled like this yes? > > Asm->OutStreamer.AddComment("foo") > Asm->EmitFoo(); > > -eric That should work at the moment that you are emitting the instructions. But what would you do when you are manipulating a

Ok I think we have some common ground - CSE should choose the aliased pointer over the non-aliased one because we don't want the no-aliasing information to creep outwards from the inlined callsite. I'll put together a patch in the coming days and add y'all as reviewers so you get visibility. Cheers, -Neil. On Wed, Jan 22, 2020 at 4:47 PM Jeroen Dobbelaere < Jeroen.Dobbelaere at

Hi, I am trying to make my tablegen files more flexible and for that I would like to have a name that in the end will be replaced with a type. If tablegen would support c preprocssing, I would do it like this: --- #define myBaseType i32 ... def imm32 : Operand<myBaseType>; def immZExt10 : ImmLeaf<myBaseType, [{return isUInt<10>(Imm);}]>; ... --- Is there a way to achieve

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