similar to: [LLVMdev] [cfe-dev] Reducing the size of LLVM and clang

On May 27, 2010, at 6:08 AM, Nicolas Capens wrote: > Hi all, > > I'm attempting to use LLVM for run-time code specialization, but I'm facing a performance hurdle. I'm currently performing the specialization during the AST to LLVM IR translation, but unfortunately this leads to relatively slow recompiles as LLVM has to perform all the heavy (optimization) passes over and

Hi Chris, Thanks for pointing me to that presentation! It helped me come up with a strategy that I believe might work: 1) Use CloneFunction() to make a copy of the original unspecialized (but optimized) function. 2) Specialize it using a custom function pass which identifies the specialization parameters and substitutes them with given run-time constants. 3) Run the function through a

On Jun 13, 2008, at 12:27 AM, Nicolas Capens wrote: > Hi all, > > When trying to generate a VFCmp instruction when UnsafeFPMath is set > to true I get an assert “Unexpected CondCode” on my x86 system. This > also happens with UnsafeFPMath set to false and using an unordered > compare. Could someone look into this? Have you filed a bug? > > While I’m at it, is there

Hi Nate! I don't see how that would work. Select doesn't work per element. Say we're trying to vectorize the following C++ code: if(v[0] < 0) v[0] += 1.0f; if(v[1] < 0) v[1] += 1.0f; if(v[2] < 0) v[2] += 1.0f; if(v[3] < 0) v[3] += 1.0f; With SSE assembly this would be as simple as: movaps xmm1, xmm0 // v in xmm0 cmpltps xmm1, zero // zero =

Looks perfect to me! well, a couple of questions: Why a noop, rather than int3/ud2/etc? Might be worth using the existing code that places such an instruction when building at -O0? & you mention that this causes problems on Windows - but ICF done by the Windows linker does not cause such problems? (I'd have thought they'd result in the same situation - two functions described as being

Hi all, We are looking to try and reduce the size of the clang and LLVM libraries and were wondering if anyone had any advice on how to do this. All we want is to be able to compile from a single language to a single back-end and for that back-end to emit instructions; we don't care about anything else. Currently we are building LLVM to use only our target, so that is OK. Is it possible to

>Hi folks, > >Our LLVM compiler creates a special debug section, which depends on a >certain >text section. This debug section is created with the SHF_LINK_ORDER >flag, and >sh_link field in the section header points to the correct section. > >When linking the program with the linker flag '-gc-sections', lld can >garbage- >collect unused sections. In my

On Mon, Mar 6, 2017 at 5:54 PM, Moritz Angermann <moritz.angermann at gmail.com > wrote: > Hi Peter, > > I’ve just experimented with this a bit: > > Say we would end up with the following assembly: > > .section __TEXT,__text > .globl _main > > .long 1 > _main: > inc %eax > ret > > .globl _main.dsp > .alt_entry _main.dsp

Hi Peter, This is a great proposal, thanks!. If you were worried about making the abi change have you thought about just going for an array of symbol names or hashes of symbol names where any matching symbol is considered address significant? This would sidestep the problem of keeping the symbol table indices in sync. It would be pessimistic for local symbols if the input SHT_ADDRSIG sections

Peter, Is there a way to make this flag globally available? Metadata can be fairly expensive to handle at each node when in many cases it is a global flag and not a per operation flag. > -----Original Message----- > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] > On Behalf Of Robert Quill > Sent: Thursday, September 08, 2011 3:24 AM > To: Peter

Assign the bug to me and I'll fix it in TOT next week! Thanks for narrowing it down! On Wednesday, September 22, 2010, Nicolas Capens <nicolas.capens at gmail.com> wrote: > Hi all, > > I think I figured it out: > 112804 causes 64-bit UNPCKLBW to no longer be selected for certain cases. > 112805 is benign. > 112806 causes 64-bit UNPCKHBW to no longer be selected for

Hi, I just came across a rather annoying behavior with llvm 3.9. Assuming the following samle code in test.ll: ; Lets have some global int x = 4 @x = global i32 10, align 4 ; and two strings "p = %d\n" for the prefix data, ; as well as "x = %d\n" to print the (global) x value. @.str = private unnamed_addr constant [8 x i8] c"x = %d\0A\00", align 1 @.str2 = private

I suspect that the format isn't important if you do that, but I wouldn't recommend it, at least because inlining (and other inter-procedural optimizations) are not expected to work correctly if you produce IR like that. Peter On Mon, Mar 6, 2017 at 6:44 PM, Moritz Angermann <moritz.angermann at gmail.com > wrote: > Peter, > > thanks again! Yes, we only need to refer to

Hello, I think that the approach of using a section to record address significance is a good one. I'm guessing it will have its own section type and format? If it does would it make sense to try and submit this to the GABI https://groups.google.com/forum/#!forum/generic-abi as it could be potentially useful for other linkers, for example gold? Happy to help out with reviews. Peter On 22

On Thu, May 24, 2018 at 10:24 AM, Eric Christopher <echristo at gmail.com> wrote: > Hi Peter, > > Thanks for doing this! > > On Wed, May 23, 2018 at 3:07 PM Peter Collingbourne via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> >> >> On Wed, May 23, 2018 at 12:16 PM, Peter Collingbourne <peter at pcc.me.uk> >> wrote: >>

LLVM isn't going to stop generating MMX instructions all together. We can't do that. :-) If the user specifically wants MMX (by, say, using the builtins), we have to support that still. The plan to cease generating MMX for generic vectors is a work-in-progress right now. It's not in 2.8. -bw On Sep 21, 2010, at 4:24 PM, Reid Kleckner wrote: > This thread confuses me. I thought

This thread confuses me. I thought Chris said that LLVM 2.8 will not lower generic vectors to MMX because it breaks x87 code, and I didn't see an answer to your question about a switch to tell the code generator otherwise. However, you're complaining that MMX performance is subpar, even though LLVM 2.8 isn't supposed to generate MMX instructions. Can someone clarify the situation

> On Mar 6, 2017, at 7:56 PM, James Y Knight via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Oh, that's great that it's possible to implement properly, now. Does it actually work for > > It'd be cool if LLVM hooked up its generic section handling support to this feature now, so that the only global symbols that *didn't* get marked as .alt_entry were

On Sep 21, 2010, at 5:30 PMPDT, Bill Wendling wrote: > LLVM isn't going to stop generating MMX instructions all together. We can't do that. :-) If the user specifically wants MMX (by, say, using the builtins), we have to support that still. The plan to cease generating MMX for generic vectors is a work-in-progress right now. It's not in 2.8. > > -bw Right, early on there

I think the simplest fix is something like this: diff --git a/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/lib/Transforms/Instrumentation/SanitizerCoverage.cpp index c6f0d17f8fe..e81957ab80a 100644 --- a/lib/Transforms/Instrumentation/SanitizerCoverage.cpp +++ b/lib/Transforms/Instrumentation/SanitizerCoverage.cpp @@ -256,6 +256,7 @@ SanitizerCoverageModule::CreateSecStartEnd(Module