search for: pessimise

Displaying 20 results from an estimated 20 matches for "pessimise".

Did you mean: pessimist
2013 Feb 20
0
[LLVMdev] [RFC] NoBuiltin Attribute
...d prefer to annotate fewer things - but probably a relatively small issue?) and then any direct call to the specific functions you care about. If you do this then, yes, you can inline in both ways (inlining other functions into the "don't simplify my calls" function without having to pessimise the inlined code and inline the function into its callers without having to pessimise those either) correctly/optimally. Just comes at the compile-time cost of annotating all calls to relevant builtins and all indirect calls. Dandy - sorry for adding to the confusion. - David -------------- next...
2013 Feb 20
2
[LLVMdev] [RFC] NoBuiltin Attribute
On Feb 20, 2013, at 8:40 AM, David Blaikie <dblaikie at gmail.com> wrote: > Sure, if you're willing to sacrifice the possible simplification of all indirect calls in any function that has even one nobuiltin requirement. > I don't understand what you mean by this. > 1) annotate calls > Pro: you can inline calls without pessimizing the function you inline into > Con:
2014 May 10
2
[LLVMdev] Replacing Platform Specific IR Codes with Generic Implementation and Introducing Macro Facilities
On 10 May 2014, at 16:18, Tim Northover <t.p.northover at gmail.com> wrote: > Actually, I really agree there. I considered it recently, but decided > to leave it as an intrinsic for now (the new IR expansion pass happens > after most optimisations so there wouldn't be much benefit, but if we > did it earlier and the mid-end understood what an ldrex/strex meant, I > could
2019 May 13
3
Delinearization validity checks in DependenceAnalysis
...h some examples showing an incorrect delinearization that's possible without those checks? 2. Are there any concerns with putting these validity checks under an option so that we can more easily disable them and experiment? This could also help us improve LIT tests, since some of them have been pessimised to compensate for DA's inability to delinearize, and could fail to catch regressions as a result of bad changes to the data dependence analysis. Looking forward to your help on this. Thank you, Bardia Mahjour Compiler Optimizations Hydra Squad Lead IBM Toronto Software Lab bmahjour at ca.ib...
2017 Apr 25
2
RFC: Moving the module summary into the irsymtab
...do for the rest of the irsymtab. I.e. we don't need to rebuild the summary entirely if the LLVM revision changes, as I am doing for the irsymtab in D32061. However, the summary must have a correct set of reference edges in order to implement dead stripping. So the solution I have in mind is to pessimise dead stripping *for that module* if the LLVM revision is out of date. I.e. the upgraded summary would contain a reference edge from every defined symbol to every other symbol in the module. Because we had already regenerated the irsymtab as a result of the revision change, we will have an accurate...
2016 Sep 21
2
RFC: module flag for hosted mode
(summarising IRC) Rethinking a little, I would be inclined to agree that combined hosted and freestanding modules should not be compiled in hosted mode. Here's one scenario where we may break: suppose I LTO-link an implementation of memset compiled with -ffreestanding with a program compiled with -fhosted. With the proposed rule, the loop idiom recognizer may transform the body of the memset
2017 Jul 12
5
[LLD] Linker Relaxation
Hi, On Wed, Jul 12, 2017 at 2:21 AM, Rui Ueyama via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Thanks, Bruce. This is a very interesting optimization. > > lld doesn't currently have code to support that kind of code shrinking > optimization, but we can definitely add it. It seems that essentially we > need to iterate over all relocations while rewriting
2013 Jul 10
2
[LLVMdev] lower-lever IR (A-normal form)
Hi, i would like to ask you, if i can get a lower-level representation than the llvm IR.For example, having the following instruction in the llvm IR, call void @llvm.memcpy.i32(i8* %19, i8* getelementptr inbounds ([2 x [2 x [3 x i8]]]* @main.s, i32 0, i32 0, i32 0, i32 0), i32 12, i32 1) i would like to get something like this (in A-normal form (without nested instructions):%temp = i8*
2019 May 15
3
Delinearization validity checks in DependenceAnalysis
...h some examples showing an incorrect delinearization that's possible without those checks? 2. Are there any concerns with putting these validity checks under an option so that we can more easily disable them and experiment? This could also help us improve LIT tests, since some of them have been pessimised to compensate for DA's inability to delinearize, and could fail to catch regressions as a result of bad changes to the data dependence analysis. Looking forward to your help on this. Thank you, Bardia Mahjour Compiler Optimizations Hydra Squad Lead IBM Toronto Software Lab bmahjour at ca.ib...
2017 May 01
3
RFC: Moving the module summary into the irsymtab
...the Apple ecosystem, we claim backward compatibility and want > ThinLTO static archive built with 4.0 to work seamlessly with 5.0, 6.0, > etc. > Sure, the design expressly allows for that. The result will not necessarily be optimal, but it will work. So the solution I have in mind is to pessimise dead stripping *for that >> module* if the LLVM revision is out of date. I.e. the upgraded summary >> would contain a reference edge from every defined symbol to every other >> symbol in the module. Because we had already regenerated the irsymtab as a >> result of the revisi...
2014 May 10
2
[LLVMdev] Replacing Platform Specific IR Codes with Generic Implementation and Introducing Macro Facilities
On 10 May 2014, at 18:14, Tim Northover <t.p.northover at gmail.com> wrote: >> The easiest solution would be to extend the cmpxchg instruction with a >> weak variant. It is then trivial to map load, modify, weak-cmpxchg to >> load-linked, modify, store-conditional (that is what weak cmpxchg was >> intended for in the C[++]11 memory model). > > That would
2018 May 31
0
Proposal for address-significance tables for --icf=safe
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
2019 May 16
2
Delinearization validity checks in DependenceAnalysis
...ing > an incorrect delinearization that's possible without those checks? > 2. Are there any concerns with putting these validity checks under an > option so that we can more easily disable them and experiment? This could > also help us improve LIT tests, since some of them have been pessimised to > compensate for DA's inability to delinearize, and could fail to catch > regressions as a result of bad changes to the data dependence analysis. > > Looking forward to your help on this. > > Thank you, > > Bardia Mahjour > Compiler Optimizations > Hydra Squ...
2006 May 12
5
How is Actionpack is not thread-safe? @@allow_concurrency?
Hi, I found many references on the Web to the fact that "Rails is not thread-safe". However, I have not found an explanation _why_ it isn''t? What happens if multiple requests are handled concurrently by ActionPack? Assuming that the code I execute in my controller methods is thread safe, is this ok? If not -- what happens? The following makes it sound like the issue is
2017 Aug 14
2
[RFC] The future of the va_arg instruction
On 9 August 2017 at 19:38, Friedman, Eli <efriedma at codeaurora.org> wrote: > On 8/9/2017 9:11 AM, Alex Bradbury via llvm-dev wrote: >> >> Option 3: Teach va_arg to handle aggregates >> * In this option, va_arg might reasonably be expected to handle a >> struct, >> but would not be expected to have detailed ABI-specific knowledge. e.g. >> it
2016 Sep 16
2
RFC: module flag for hosted mode
+Eric and Akira (for thoughts on module flags) > On 2016-Sep-16, at 12:47, Mehdi Amini <mehdi.amini at apple.com> wrote: > >> On Sep 16, 2016, at 12:30 PM, Peter Collingbourne <peter at pcc.me.uk> wrote: >> >> In PR30403 we've been discussing how to encode -ffreestanding when using LTO. This bit is currently dropped during LTO because its only
2019 May 22
2
Delinearization validity checks in DependenceAnalysis
...ing > an incorrect delinearization that's possible without those checks? > 2. Are there any concerns with putting these validity checks under an > option so that we can more easily disable them and experiment? This could > also help us improve LIT tests, since some of them have been pessimised to > compensate for DA's inability to delinearize, and could fail to catch > regressions as a result of bad changes to the data dependence analysis. > > Looking forward to your help on this. > > Thank you, > > Bardia Mahjour > Compiler Optimizations > Hydra Squad...
2019 Jun 07
4
[nbdkit PATCH v2 0/2] Reduce network overhead with MSG_MORE/corking
This time around, the numbers are indeed looking better than in v1; and I like the interface better. Eric Blake (2): server: Prefer send() over write() server: Group related transmission send()s server/internal.h | 7 +++- server/connections.c | 51 +++++++++++++++++++++++++--- server/crypto.c | 11 ++++--
2018 May 22
7
Proposal for address-significance tables for --icf=safe
Hi all, Context: ld.gold has an --icf=safe flag which is intended to apply ICF only to sections which can be safely merged according to the guarantees provided by the language. It works using a set of heuristics (symbol name matching and relocation scanning). That's not only imprecise but it only works with certain languages and is slow due to the need to demangle symbols and scan
2020 May 29
5
[cfe-dev] [RFC] Loading Bitfields with Smallest Needed Types
On Fri, May 29, 2020 at 4:00 PM Richard Smith <richard at metafoo.co.uk> wrote: > > On Fri, 29 May 2020 at 11:06, John McCall via llvm-dev <llvm-dev at lists.llvm.org> wrote: >> >> On 28 May 2020, at 18:42, Bill Wendling wrote: >> >> > On Tue, May 26, 2020 at 7:49 PM James Y Knight via llvm-dev >> > <llvm-dev at lists.llvm.org> wrote: