search for: preconditioning

Hi all,Is there any way to tell LLVM some additional information about the variables in the code in order to make better optimization?For example, if my function has a certain precondition (such as x>0) then it will be possible to better optimize the code given that information (which the compiler does not know).I am new in this field and I don't know if there are ways to tell the compiler

Thank you, it was what I really was searching for :) However, I don't know if I well understood. I've find this link in the second link which seemed what i was looking for: http://nondot.org/sabre/LLVMNotes/BuiltinUnreachable.txt .If I put around the code block (inside my function with precondition (x>0 && y>0)) a contruct like that that use __builtin_unreachable: int foo(int

You may want to check this out: http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-October/053924.html and also http://llvm.org/PR810 - xi On 10/22/12 6:05 PM, Niko Zarzani wrote: > Hi all, > Is there any way to tell LLVM some additional information about the > variables in the code in order to make better optimization? > For example, if my function has a certain precondition (such

On Mon, Oct 22, 2012 at 9:33 PM, Niko Zarzani <koni10 at hotmail.it> wrote: > Thank you, it was what I really was searching for :) > > However, I don't know if I well understood. I've find this link in the > second link which seemed what i was looking for: > http://nondot.org/sabre/LLVMNotes/BuiltinUnreachable.txt . > If I put around the code block (inside my

Hi Niko, Do you mean branch prediction, i.e. __builtin_expect [1]? Many compilers support it, I think clang (LLVM's C/C++ frontend) is among them. - D. [1] http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html 2012/10/23 Niko Zarzani <koni10 at hotmail.it>: > Hi all, > Is there any way to tell LLVM some additional information about the > variables in the code in order to

If you're on the new Makefile system, you will want to update your Makefile.rules. The patch below provides some important fixes for parallel builds and dependencies. It also adds some new features like the -local targets. For example, you can now build "all-local" to build the local directory without recursing into subdirectories. See the comments below for details of the change.

Hello everbody, i'm currently using the anova()-test for a small data.frame of 40 rows and 2 columns. It works well, but is there any preconditions for a valid variance analysis, that i should consider? Thank you for your answer, Daniel

1) I find typo in Makefile.rules in printvars rule: - $(Echo) "Preconditions: " '$(Preconditions)' + $(Echo) "PreConditions: " '$(PreConditions)' 2) In Makefile.config.in PROJ_SRC_DIR define for LLVM build mode as PROJ_SRC_DIR := $(subst //,/,$(LLVM_SRC_ROOT)/$(patsubst $(PROJ_OBJ_ROOT)%,%,$(PROJ_OBJ_DIR))) and for other project build mode as PROJ_SRC_DIR

I noticed the "Joining a Samba DC to an Existing Active Directory" wiki page was updated yesterday (October 9, 2016.) Under "Preconditions" header, the third bullet point is "If Samba is already configured on this host, remove any existing configuration and databases." Well, "configuration" is start forward, meaning the smb.conf file but, what

During some discussions and handwaving, including discussions with some experts on the Xenserver/XCP storage architecture, we came up with what we think might be a plausible proposal for an architecture for communication between toolstack and driver domain, for storage at least. I offered to write it up. The abstract proposal is as I understand the consensus from our conversation. The concrete

Hi all, I have a question about dereferenceable metadata on load instruction. I have a patch (https://reviews.llvm.org/D31539) for LICM that hoists loads with !invariant.group. The motivation example is devirtualization: struct A { virtual void foo(); }; int bar(); void indirect(A &a) { while(bar()) a.foo(); } With -O2 -fstrict-vtable-pointers we get: define void

Brian Ripley wrote (to somebody asking about "effect sizes"): > ... > Given that, I wonder if you are used to standard terminology. Good point. But I think for many of us there is more behind that. I personally belong to an (apparently fairly large) group of R users who may be enthusiastic, but are statistical laymen due to a lack of formal education in the area. The

Hi Sanjay, You used Alive correctly, of course :) At this moment we cannot give you the best precondition. It’s on the todo list, but it’s not even started yet. It’s a much harder problem to solve. We do have a mode to compute the best set of nsw/nuw/exact attributes in the transformed expression, but it’s not enabled on the web interface yet (InstCombine was missing quite a few cases last

On Fri, Mar 31, 2017 at 10:23 AM, Sanjoy Das <sanjoy at playingwithpointers.com > wrote: > Hi Piotr, > > On March 31, 2017 at 9:07:42 AM, Piotr Padlewski > (piotr.padlewski at gmail.com) wrote: > > Hi all, > > I have a question about dereferenceable metadata on load instruction. I > > have a patch (https://reviews.llvm.org/D31539) for LICM that hoists >

This might be hard cases making bad law, but the loop: void f (unsigned short *x, int *l) { int c = *l; int i; for (i = 0; i < c; i++) if (x[i]) x[i]++; } is converted to decrement-and-branch form by LoopStrengthReduce while: void f (unsigned short *x, int *l) { int i; for (i = 0; i < *l; i++) if (x[i]) x[i]++; } isn't.

Not sure how off-topic this is, but should we consider/have we considered porting our InstCombines to Alive? The PLDI '15 paper even demos C++ extraction from Alive theorems. I think it'd be a small step from that to extracting tightly optimized VM code, not unlike what Tablegen emits. Everything would be so clean and readable and organized. And edge cases can still be handled manually,

+1 to alive2.llvm.org On Thu, Jun 18, 2020 at 8:11 AM John Regehr via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > > If we can get Alive1 up there too, that would be even better. I still > > use that to try to prove things where it's not obvious how to express > > the relationships in pure LLVM IR: > > https://rise4fun.com/Alive/NDu > > I don't

Hi folks, I wonder how to get the statistic of which pass has been "really" applied and which one is not. For instance, I try to apply 20 llvm passes on a single C source code. But since the precondition of each pass may not be satisfied (try loop-unrolling to a source code without loop), some of these pass may not affect the final result. How to know which pass affect and

Hi all, I'm a little surprised at > NULL == c("a", "b") logical(0) > all(NULL == c("a", "b")) [1] TRUE Reading the documentation for all() this was not clear for me to be expected. Originally the question came up when using > match.arg(NULL, c("a", "b")) [1] "a" where I had thought an error would occur. So

Sorry, lots of questions these days. Is there a normal approach for preconditions? In JUnit, I might put a few assertions in the setUp() just to make sure that the test ''data'' I''ve created meets expectations before going to test it. So, for instance, I''ve got an object that is audited using acts_as_audited and I''d like to test the XML that results