similar to: [RFC] Increase the scope of Value::getPointerXXX methods

Hi, everyone, I'd like to propose adding a nofree function attribute to indicate that a function does not, directly or indirectly, call a memory-deallocation function (e.g., free, C++'s operator delete). Clang/LLVM can currently misoptimize functions that:  1. Have a reference argument.  2. Free the memory backing the object to which the reference is bound during the function's

[+Richard] On 07/11/2018 08:29 AM, Sanjoy Das wrote: > I'm not sure if nosynch is sufficient. What if we had: > > void f(int& x) { > if (false) { > int r0 = x; > } > } > > // other thread > free(<pointer to x>); > > The source program is race free, but LLVM may speculate the read from > x (seeing that it is dereferenceable) creating a

Thanks, Richard. Based on the feedback from this thread, I'll move forward with the patches for nofree, nosync, adding a new corresponding dereferenceable attribute (my suggestion is to name this dereferenceable_on_entry; suggestions welcome), and updating Clang is emit this new attribute instead of the current one.  -Hal On 07/11/2018 06:43 PM, Richard Smith wrote: > On Wed, 11 Jul 2018

Hi, We've recently encountered a problem in our compiler where the line number in debug info jumps back and force even at O0. This is caused by DAG node ordering not being properly kept during legalization and instruction selection. There are still uncaught cases after applying the patch mentioned here. So I have decided to implement the approach suggested by Andy as below. i.e. maintain the

Hi Talin, > I find that I call the static methods in ConstantExpr a *lot* without going > through IRBuilder - hundreds of times in my frontend. My language generates a > lot of static data - reflection information, trace tables for the garbage > collector, dispatch tables, runtime annotations, static object instances, and so > on. (In fact there's a special helper class

Hi Eric, Sorry I wasn't clear. The problem happened in the "source" pre-RA scheduler, which relies on DAG node ordering to schedule the nodes. Xiaoyi From: Eric Christopher [mailto:echristo at gmail.com] Sent: Tuesday, April 30, 2013 12:54 AM To: Guo, Xiaoyi Cc: LLVM Developers Mailing List Subject: Re: [LLVMdev] [PATCH] Propagate DAG node ordering during legalization and

You need to configure with --enable-llvm. (It would still be nice if V1DI_pointer_node was defined; I'll take a look at that.) On May 20, 2010, at 1:04 PM, Anatoly Yakovenko wrote: > i am getting this compilation error: > > > gcc -c -g -O2 -DIN_GCC -DCROSS_DIRECTORY_STRUCTURE -W -Wall > -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic >

On Tue, Apr 30, 2013 at 12:48 AM, Guo, Xiaoyi <Xiaoyi.Guo at amd.com> wrote: > Hi,**** > > ** ** > > We’ve recently encountered a problem in our compiler where the line number > in debug info jumps back and force even at O0. This is caused by DAG node > ordering not being properly kept during legalization and instruction > selection. There are still uncaught cases

i am getting this compilation error: gcc -c -g -O2 -DIN_GCC -DCROSS_DIRECTORY_STRUCTURE -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Wold-style-definition -Wmissing-format-attribute -DHAVE_CONFIG_H -I. -I. -I../../llvm-gcc-4.2-2.7.source/gcc -I../../llvm-gcc-4.2-2.7.source/gcc/.

On Apr 30, 2013, at 11:00 AM, "Guo, Xiaoyi" <Xiaoyi.Guo at amd.com> wrote: > Hi Eric, > > Sorry I wasn’t clear. The problem happened in the “source” pre-RA scheduler, which relies on DAG node ordering to schedule the nodes. In your case, Eric's suggestion was effectively "start implementing fast-isel". Which is not a bad idea if you want to reduce compile

I'd like to propose that we create a new Performance Guide document. The target of this document will be frontend authors, not necessarily LLVM contributors. The content will be a collection of items a frontend author might want to know about how to generate LLVM IR which will optimize well. Some ideas on topics that might be worthwhile: - Prefer sext over zext when value is known to be

I'd like to propose that we add an attribute which expresses the notion that the specified value is /either/ null or dereferenceable up to a fixed size. (Note the xor.) Our current dereferenceable(n) attribute doesn't quite fit the bill, it implies that the pointer is non-null. Similarly, our nonnull attribute says nothing about dereferenceability. There are two syntax proposals

If there are any students looking for ideas, here a couple of projects you might consider. p.s. Anyone know where in the repo the OpenProjects page is? I'd expected it to be the docs/ folder of the LLVM repo, but it wasn't. Transactional Memory Optimization Intel recently introduced transactional memory support in hardware. This project would consist of implementing optimizations

Hi Attached is a patch that adds aliases to the API for methods that look like attribute accessors. So a_frame.set_title(''The title'') # currently a_frame.title = ''The title'' # now an alternative textctrl.get_value # currently textctrl.value # now an alternative Also, C++ methods named ''IsXXX'' are now exposed in ruby with

Hi all, At the dev meeting I promised to update everyone on where my work with opaque pointers is right now. It's taken me a while, but at least it's the same year! Current Status ============== I've put two branches up at https://github.com/TNorthover/llvm-project: "opaque-ptr" which has most of the real work so far; and "opaque-ptr-always" that additionally has

Hi, There are several optimizations where we try to load speculatively. There are also two similar functions to determine whether it's a safe transformation: * isSafeToLoadUnconditionally * isSafeToSpeculativelyExecute isSafeToLoadUnconditionally tries to take load alignment into account but fails to do this in some cases. It checks alignment for pointers derived from allocas and global

Hi Philip, > On Mar 22, 2016, at 4:43 PM, Philip Reames via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > If there are any students looking for ideas, here a couple of projects you might consider. > > p.s. Anyone know where in the repo the OpenProjects page is? I'd expected it to be the docs/ folder of the LLVM repo, but it wasn't. Is it what you're

Philip Reames wrote: > T.M.K., there's no direct way to test it. There is. See the 'unittests/' directory which contains the C++ unit tests. See unittests/IR/UserTest.cpp for an example that builds up IR from a .ll-in-a-C-string then queries C++ API operations on it. Nick You have to construct a > transformation which happens with the information you added and not >

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

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