similar to: [LLVMdev] Vector instructions

On Jun 26, 2008, at 1:56 PM, Stefanus Du Toit wrote: > Hi, > > I have some questions as to the definition of various vector > instructions. In particular, I believe there are some gaps and > inconsistencies in the vector instructions, and I'm interested in > hearing whether you agree that these should be improved or whether > there are other ways to solve these problems.

Hi Dan, Thanks for your comments. I've responded inline below. On 26-Jun-08, at 6:49 PM, Dan Gohman wrote: > On Jun 26, 2008, at 1:56 PM, Stefanus Du Toit wrote: >> >> === >> 1. Shufflevector only accepts vectors of the same type >> >> I would propose to change the syntax from: >> >>> <result> = shufflevector <n x <ty>>

On Jun 27, 2008, at 8:02 AM, Stefanus Du Toit wrote: >>>> <result> = shufflevector <a x <ty>> <v1>, <b x <ty>> <v2>, <d x >>>> i32> >>>> <mask> ; yields <d x <ty>> >>> >>> With the requirement that the entries in the (still constant) mask >>> are >>> within

Hi, We would like to extend the vector operations in llvm a bit. We're hoping to get some feedback on the right way to go, or some starting points. I had previously had some discussion on this list about a subset of the changes we have in mind. All of these changes are intended to make target-independent IR (i.e. IR without machine specific intrinsics) generate better code or be

On Jul 21, 2008, at 1:21 PM, Stefanus Du Toit wrote: > Hi, > > We would like to extend the vector operations in llvm a bit. We're > hoping to get some feedback on the right way to go, or some starting > points. I had previously had some discussion on this list about a > subset of the changes we have in mind. > > All of these changes are intended to make

Hi Mon Ping, Generalizing shufflevector would be great. I have an additional suggestion below. On 29-Sep-08, at 11:11 PM, Mon Ping Wang wrote: > I am proposing to extend the shuffle vector definition to be > <result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <m x i32> > <mask> ; yields <m x <ty>> > > The

I agree further generalization seems like a very good idea. But I'd like to see what Mon Ping proposed implemented first so we have a better idea of the implementation cost. Thanks, Evan On Sep 30, 2008, at 6:44 AM, Stefanus Du Toit wrote: > Hi Mon Ping, > > Generalizing shufflevector would be great. I have an additional > suggestion below. > > On 29-Sep-08, at 11:11

On Jun 24, 2009, at 12:47 AM, Duncan Sands wrote: > Hi Nick, > >> Now that icmp and fcmp have supported returning vectors of i1 for a >> while, > > the code generators don't know how to codegen vectors of i1, so does > this actually work? No, but there are no clients of them yet. -Chris

On Jun 24, 2009, at 10:02 AM, Chris Lattner wrote: > > On Jun 24, 2009, at 12:47 AM, Duncan Sands wrote: > >> Hi Nick, >> >>> Now that icmp and fcmp have supported returning vectors of i1 for a >>> while, >> >> the code generators don't know how to codegen vectors of i1, so does >> this actually work? > > No, but there are no

Hi, The current definition of shuffle vector is <result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <n x i32> <mask> ; yields <n x <ty>> The first two operands of a 'shufflevector' instruction are vectors with types that match each other and types that match the result of the instruction. The third

On Monday 21 July 2008 15:21, Stefanus Du Toit wrote: > We would like to extend the vector operations in llvm a bit. We're > hoping to get some feedback on the right way to go, or some starting > points. I had previously had some discussion on this list about a > subset of the changes we have in mind. Woohoo! We've been interested in talking about this for some time. >

On Mon, Jul 21, 2008 at 1:21 PM, Stefanus Du Toit <stefanus.dutoit at rapidmind.com> wrote: > 1) Vector shl, lshr, ashr > > I think these are no-brainers. We would like to extend the semantics > of the shifting instructions to naturally apply to vectors as well. > One issue is that these operations often only support a single shift > amount for an entire vector. I assume it

Hi Stefanus, Thanks for the info. I still think it's a bug though. Take for example a case where the vectors each have four elements. The values in Mask[] can range from 0 to 7, while HLSMask only has 4 elements. So LHSMask[Mask[i]] can go out of bounds, no? Cheers, Nicolas From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On Behalf Of Stefanus Du

Hi Stefanus, Thanks for verifying this. Could you patch this or should I open a new bug report and find a generic solution first? Cheers, Nicolas From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On Behalf Of Stefanus Du Toit Sent: woensdag 1 april 2009 18:59 To: LLVM Developers Mailing List Subject: Re: [LLVMdev] Shuffle combine On 1-Apr-09, at 12:42

On 1-Apr-09, at 12:42 PM, Nicolas Capens wrote: > Hi Stefanus, > > Thanks for the info. I still think it’s a bug though. Take for > example a case where the vectors each have four elements. The values > in Mask[] can range from 0 to 7, while HLSMask only has 4 elements. > So LHSMask[Mask[i]] can go out of bounds, no? Good point! One easy way to fix this would be to use:

Hi Nicolas, On 2-Apr-09, at 6:04 PM, Nicolas Capens wrote: > Thanks for verifying this. Could you patch this or should I open a > new bug report and find a generic solution first? I don't have write access so the best I could do would be to submit a patch, and I'm crazy busy at the moment. I actually think the check I described below is fine and would fix this bug (but

On 23-Jul-08, at 12:15 PM, David Greene wrote: > On Monday 21 July 2008 15:21, Stefanus Du Toit wrote: > >> We would like to extend the vector operations in llvm a bit. We're >> hoping to get some feedback on the right way to go, or some starting >> points. I had previously had some discussion on this list about a >> subset of the changes we have in mind. >

Hi, I agree that the more general shufflevector is more useful. I narrowed the original proposal a little bit because of the concern for the implementation cost. However, the slightly narrowed definition will probably require falling backing to generate insert and extracts for complex masks so it is possible that there will be no extra cost in supporting the more general definition.

Hi Nicolas, On 1-Apr-09, at 7:34 AM, Nicolas Capens wrote: > I’m having some trouble understanding the following lines in > InstructionCombining.cpp, which possibly contain a bug: > > if (Mask[i] >= 2*e) > NewMask.push_back(2*e); > else > NewMask.push_back(LHSMask[Mask[i]]); > > When Mask[i] is bigger than the size of LHSMask it reads out of > bounds

Hi all, I'm having some trouble understanding the following lines in InstructionCombining.cpp, which possibly contain a bug: if (Mask[i] >= 2*e) NewMask.push_back(2*e); else NewMask.push_back(LHSMask[Mask[i]]); When Mask[i] is bigger than the size of LHSMask it reads out of bounds on that last line. I believe the first line is there to try to prevent that but then it