search for: precondit

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 preconditions (such as by using some preprocessing directives).Thank you in advance,N...

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 x, int y){ if(x>0 && y>0){ ...function codeblock... } { __builtin_unreachable (); } } I can get the optimization without really having a branch jump in the machine cod...

...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 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 preconditions (such as by using some preprocessing directives...

...t 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 x, int y){ > > if(x>0 && y>0){ > ...function codeblock... > } > { > __builtin_unreachable (); > } > > } > > I can ge...

...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 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 preconditions (such as by using some preprocessing directives)....

...######################################################################## > -# Default Targets: > -# The following targets are the standard top level targets for > -# building. > -########################################################################### > - > - > -# Ensure all preconditions are met > -all:: preconditions > - > -# Make sure all the user-target rules are double colon rules > -all :: preconditions > -clean:: preconditions > -install :: preconditions > -uninstall :: preconditions > -check:: preconditions > -dist:: preconditions > -distche...

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...

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 "databases" is the statement referring to? -- _____...

...ckend directory, in the same transaction as it creates the frontend. Set by the driver domain in response to a plug request; may be deleted by the toolstack. DEPRECATED, see below. The operations: prepare Creates a vdi from a target. Preconditions: state ENOENT request ENOENT Request (xenstore writes by toolstack): request = "prepare" t/* as appropriate Results on success (xenstore writes by driver domain): request ENOENT } applies to success from al...

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

...arge) group of R users who may be enthusiastic, but are statistical laymen due to a lack of formal education in the area. The half-knowledge that I have is often sufficient to see that many otherwise nice sources of statistical knowledge are dangerously incomplete when it comes to explaining the preconditions required for applying a certain technique (One example: The extensive NIST handbook at http://www.itl.nist.gov/div898/handbook/ fails to mention that the Wilcoxon rank sum test assumes a continuous distribution underlying the sample) This is not to speak of how to correctly interpret the res...

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 time I c...

...ion: > > ... > > [snip] > > > > On the other hand, after performing my LICM of !invariant.group load, GVN > > hoists the second load and I am not sure why it is legal then. > > I suspect what's going on is that we first canonicalize the loop to: > > if (precondition) { > do { > vptr = load vtable; > fptr = *vptr; > ... > } while (backedge_condition); > } > > after which it is safe to transform the program to (modulo aliasing): > > if (precondition) { > vptr = load vtable; > fptr = *vptr; > do { &g...

...icmps, thanks to IndVarSimplify. if (ICmpInst *CI = dyn_cast<ICmpInst>(LF.UserInst)) if (CI->isEquality()) { and this is happening for the first loop but not the second. The reason is that the second loop still has two loads of *l by the time IndVarSimplify is run; one for the precondition of the rotated loop and one for the loop exit. This means that IndVarSimplify can't tell that the precondition (skip the loop if *l <= 0) is operating on the same *l as the loop exit, and therefore can't work out that *l is the trip count. The two "*l"s are only fused by G...

...lt;spatel at rotateright.com> wrote: > > > On Fri, Jan 6, 2017 at 2:30 AM, Nuno Lopes <nuno.lopes at ist.utl.pt> wrote: > >> 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 mis...

...e (or he, more > accurately) wants to keep supporting it. We might prefer to try to just > support use cases such as your example in alive2. alive1 is python2 though, so someone would need to port it to python3 first. Perhaps a better alternative would be to finish adding missing support for Preconditions/constants into alive2 > John Roman > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

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 which one is ignored? Does Llvm have this kind of statistic? Thanks. Best, Kecheng

...t 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 could someone please help me and explain what I have overlooked. Should I realy have to use is.null() as a precondition check here when a NULL argument could arise. Regards, Matthias PS: the same behaviour occurs in R 1.9.1 and R 2.1.0 devel: 2005-02-07 > version _ platform i686-pc-linux-gnu arch i686 os linux-gnu system i686, linux-gnu status major 2 minor 0.1 year 2004...

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 t...