similar to: [LLVMdev] What is the optimization level means?

I want the optimization to be turned on at -O1 and above. In my case, it is a target independent back-end pass. (Eg: MachinePipeliner) On 2017-01-04 18:10, Mehdi Amini wrote: >> On Jan 4, 2017, at 4:03 PM, Sumanth Gundapaneni via llvm-dev >> <llvm-dev at lists.llvm.org> wrote: >> >> I see the BackendUtil.cpp of Clang creates the TargetMachine with >> the

I see the BackendUtil.cpp of Clang creates the TargetMachine with the optimization level based on below mentioned logic CodeGenOpt::Level OptLevel = CodeGenOpt::Default; switch (CodeGenOpts.OptimizationLevel) { default: break; case 0: OptLevel = CodeGenOpt::None; break; case 3: OptLevel = CodeGenOpt::Aggressive; break; } As per my understanding, the correspondence between

getOptLevel() gets the level from TargetMachine which is created by the Backendutil in clang with either "Default", "None" or "Aggressive". Threre is no correspondence for "Less". This boils down to , if I pass "-O1", the Target Machine is created with CodeGenOpt::Default. I am available on IRC @ sgundapa. -----Original Message----- From:

Here is a problem scenario. I want to enable a backend pass at -O2 or above. if (TM->getOptLevel() >= CodeGenOpt::Default) addPass(&xxxxx); This pass will be run at -O1 too since clang is creating the TargetMachine with CodeGenOpt::Default for -O1. --Sumanth G -----Original Message----- From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com] Sent: Friday, January 6, 2017

Folks, I'm at the point in developing llvmc (Compiler Driver) where I need to get the details on the specific optimization arguments that the -O family of options should (by default) issue to "opt". I'm soliciting your feedback on this so I can start testing optimization. Hopefully you can provide it by early this coming week. For clarity, the -O options are currently defined

Hi all, These two cmake configuration are using different optimization levels (O2 vs O3). What is the rational for that? I know that O1 is "supposingly" more friendly for debugging, but I don't think we make such claim for O2 vs O3, are we? I'd expect RelWithDebInfo to be what the name says, i.e. Release + debug-information. -- Mehdi

+ OptLevel = opt[1] - '0'; Please check and reject things like -OX at least in the gold plugin. Can you add a test showing that * createLowerBitSetsPass is run at -O0 * the addLateLTOOptimizationPasses passes are run at -O1, but not -O0 I think the patch is fine otherwise, but wait for a review from someone on the ld64 side (Duncan, Manman or Bob for example). Thanks, Rafael

On Sat, 14 Aug 2004, Reid Spencer wrote: > I'm at the point in developing llvmc (Compiler Driver) where I need to > get the details on the specific optimization arguments that the -O > family of options should (by default) issue to "opt". I'm soliciting > your feedback on this so I can start testing optimization. Hopefully you > can provide it by early this coming

On Thu, Mar 19, 2015 at 11:12 AM Rafael Espíndola < rafael.espindola at gmail.com> wrote: > Having the analogous of -O0/-O1/-O2/-O3 for the LTO pipeline makes > sense I think. > > I agree that something along option number 2 is probably the best. > Some questions: > > * Should "clang -O3 foo.o -o foo" use LTO with -O3? > * Should "clang foo.o -o

> -----Original Message----- > From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Mehdi > Amini via llvm-dev > Sent: Friday, January 06, 2017 11:10 AM > To: Sumanth Gundapaneni > Cc: LLVM Developers > Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level passed > from clang. > > > > On Jan 6, 2017, at 10:56 AM, Sumanth

Reid, I have one substantial change to suggest to this. I think the distinction between module-level and cross-module optimization is artificial and unnecessary in LLVM because transparent link-time optimization makes intra-module and cross-module optimizations indistiguishable. It *is* important to distinguish between fast and slow optimizations. Because of this, I would suggest a

On Tue, Jul 16, 2013 at 8:16 AM, Stéphane Letz <letz at grame.fr> wrote: > Hi, > > Our DSL emit sub-optimal LLVM IR that we optimize later on (LLVM IR ==> LLVM IR) before dynamically compiling it with the JIT. We would like to simply follow what clang/clang++ does when compiling with -O1/-O2/-O3 options. Our strategy up to now what to look at the opt.cpp code and take part of it

Hello, there are several optimization levels in lli like O0, O1, O2, O3. What does they mean? how the run time optimization is performed in LLVM JIT? I am working on a project where my goal is to study the impact of lli optimizations. here my IR is already optimized through opt. now i have to perform lli optimizations provided i am giving varying inputs at run time. so i suppose here my

Hi, Our DSL emit sub-optimal LLVM IR that we optimize later on (LLVM IR ==> LLVM IR) before dynamically compiling it with the JIT. We would like to simply follow what clang/clang++ does when compiling with -O1/-O2/-O3 options. Our strategy up to now what to look at the opt.cpp code and take part of it in order to implement our optimization code. It appears to be rather difficult to follow

Folks, I'm trying to rationalize about optimization levels and maybe we should come up with a document like this: http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html Though, I remember a discussion a few months ago, and some people recommended we had names, rather than numbers, to dissociate the idea that 3 is better than 2. Regardless, would be good to have some guidelines on what goes

Le mar. 3 avr. 2018 à 12:47, via llvm-dev <llvm-dev at lists.llvm.org> a écrit : > All, > A recent commit, D43040/r324557, changed the behavior of the gold plugin > when compiling with LTO. The change now causes the codegen optimization > level to default to CodeGenOpt::Default (i.e., -O2) rather than use the > LTO optimization level. The argument was made that the LTO

Hello, I'm trying to minimize the processing time for llc -O3 by using a three step compilation process of 1. llc input.bc -stopafter=targetlibinfo -o input.mir 2. llc -run-pass={....min passes...} input.mir -o opt.mir 3. llc -startafter=machine-opt-remark-emitter -filetype=obj opt.mir -o final.obj Examining the passes produced by llc for O1,O2,O3 I compared (with XXX = {1,2,3}): llc

On 2018-04-04 22:00, Mehdi AMINI wrote: > Le mar. 3 avr. 2018 à 12:47, via llvm-dev <llvm-dev at lists.llvm.org> a > écrit : > >> All, >> A recent commit, D43040/r324557, changed the behavior of the gold >> plugin >> when compiling with LTO. The change now causes the codegen >> optimization >> level to default to CodeGenOpt::Default (i.e., -O2)

Is there a succinct way I can get the full list of which optimization passes are applied, and in what order, for standard clang -O1, -O2, -O3? -- Larry Gritz lg at larrygritz.com

Hello Paul, François and Vedant, Thank you all for your answers. And sorry for this late reply. I wanted to dig more into the LLVM source code to get a better understanding of the debug part of it before replying/asking more questions. I have came across this https://llvm.org/docs/SourceLevelDebugging.html#debugging-optimized-code which stated that "*Basically, the debug information allows