similar to: [LLVMdev] How to handle global variables in LLVM analyses

Can you say what Benchmark or give a test case so we understand the nature of the regression? As Gerolf said, that will be important to understand what is best to do. On Fri, Jul 17, 2015, 06:43 Evgeny Astigeevich <Evgeny.Astigeevich at arm.com> wrote: > Yes, the regression is stable. I double checked this. A full benchmark > run consists of at least 10 sub-runs to validate the

Before the fix, the compiler may simply return 'noalias' for cases it can not really prove to be noalias, but actually correct by luck (or even wrong noalias, but does not result in miscompile). It would be useful to find out the set of missed noalias queries from GlobalModRef with your benchmark and examine if there is some improvement can be done. David On Fri, Jul 17, 2015 at 6:32

On Fri, Jul 17, 2015 at 9:13 AM Evgeny Astigeevich < evgeny.astigeevich at arm.com> wrote: > It’s Dhrystone. > Dhrystone has historically not been a good indicator of real-world performance fluctuations, especially at this small of a shift. I'd like to see if we see any fluctuation on larger and more realistic application benchmarks. One advantage of the flag being set is that we

Hi Chandler, I would like to run some benchmarks on ARM hardware and to look at impact of your patches on LTO. Kind regards, Evgeny Astigeevich From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On Behalf Of Chandler Carruth Sent: 15 July 2015 10:45 To: Chandler Carruth; Gerolf Hoflehner Cc: LLVM Developers Mailing List Subject: Re: [LLVMdev] GlobalsModRef

Based on function names and structures, this is some version of GCC :) Any way you can post the entire .ll file? Because it's globalsmodref, it's hard to debug without the other functions, since it goes over all the functions to determine address takenness, etc :) On Tue, Jul 21, 2015 at 3:23 PM, Michael Zolotukhin <mzolotukhin at apple.com> wrote: > Hi Chandler, > > We

Hey, thanks for benchmarking. How stable is the 2% regression? Michael ran some benchmarks with GlobalsModRef completely disabled and the only differences were in the noise. This was a complete spec2k6 run along with some others. Based on the number of benchmarks run there, I'm going to go ahead and submit these patches, but if you can clarify the impact here, we can look at potentially some

On Mon, Jul 13, 2015 at 10:21 PM Chris Lattner <clattner at apple.com> wrote: > > > On Jul 13, 2015, at 8:19 PM, Chandler Carruth <chandlerc at gmail.com> > wrote: > > > > Ok folks, > > > > I wrote up the general high-level thoughts I have about stateful AA in a > separate thread. But we need to sort out the completely and horribly broken >

Replying here, but several of the questions raised boil down to "couldn't you make the usage of GetUnderlyingObject conservatively correct?". I'll try and address that. I think this *is* the right approach, but I think it is very hard to do without effectively disabling this part of GlobalsModRef. That is, the easy ways are likely to fire very frequently IMO. The core idea is

On Jan 3, 2012, at 1:53 PM, Jianzhou Zhao wrote: > I see. I asked the question because LLVM provides several alias > analysis, and I was wondering how to decide which one should be used > for compiling most programs. > > I think the basicaa is the default one, but by looking into its code, > it is not inter-procedural or context-sensitive (I am not 100% sure), > so does not

Hello, I'm playing with alias analysis, using the following program: %i = external global int ; <int*> [#uses=2] implementation ; Functions: int %_Z3bari(int %p) { entry: %tmp.0 = load int* %i ; <int> [#uses=1] %tmp.1 = setgt int %tmp.0, 10 ; <bool> [#uses=1] br bool %tmp.1, label %then, label %UnifiedReturnBlock then:

Hi there, I am doing: opt -print-memdeps ./test.bc -analyze -globalsmodref-aa by adding globalsmodref-aa, I am hoping that globalsmodref alias analysis will be used. However, it does not turn out to be so. I found this out by adding some "errs() << " into the source code for that alias analysis. So my question is what should I do to let memory dependency analysis use

Mingxing Tan wrote: > > Hi, all; > > How can I get the number of variables in a function/module (both the > number of variables in original source program and the number of > temporal variables for ssa-form)? > Do you want the SSA values *created* by a function, those used by a function, or both? For SSA values, simply iterate over all of the instructions within the

Hello I am trying to enable globalsmodref-aa by default. globalmodref-aa is a ModulePass and therefore can be invalidated and need to be rerun. I see globalsmodref-aa is enabled in LTO passmanager by adding the analysis pass explicitly. I wonder whether globalsmodref-aa can be enabled/run based on pass dependencies, i.e. those indicated in getAnalysisUsage(). Thanks, Xin -------------- next

On Thu, 6 Nov 2003, Michelle Strout wrote: > I think some clarifications and examples would be helpful. No problem. :) > - LLVM is in SSA. It is in SSA before alias analysis has been > >>>> performed. With OA, it has been mentioned that the SSA generation > >>>> is > >>>> incorrect because it doesn't take alias analysis information into

Jack Howarth wrote: > I've had better luck compiling all of pymol 1.1r2 with > -O4 on darwin9. Everythink links and there appears to be > no regressions in the resulting code. I take it that LTO > in llvm 2.5 is still limited to dead code elimination, > correct? No. libLTO does the equivalent to opt -internalize -ipsccp -globalopt -constmerge -deadargelim -instcombine

Hello, I wrote my own pass which needs to do some loop unrolling. I can perform loop unrolling via opt: opt -mem2reg -loops -loop-simplify -loop-rotate -lcssa -loop-unroll -unroll-count=50 mytest.bc -o mytest.bc This command works perfectly. However, what I really want is to produce the **same behavior** but from my own pass (i.e., I don't want to use opt). I wrote a Module pass which

Hi, I am emitting llvm bit code using llvm-gcc -c -emit-llvm -O0 -o test.bc test.c and then optimizing it with opt -O3 -print-module test.bc in order to obtain a dump of generated IR. The resulting code has Phi nodes and is perhaps in SSA form. I want to undo the SSA form while retaining all the other optimizations. Is mem2reg the right optimization to be added after -O3, i.e., opt -O3

Hi, all; How can I get the number of variables in a function/module (both the number of variables in original source program and the number of temporal variables for ssa-form)? I’m dealing with some dataflow analysis problem and need the information of variables. Appreciate any help. Thanks. Star.Tan -------------- next part -------------- An HTML attachment was scrubbed... URL:

Hi Thanks for your answers so far. I am currently stumbling into new questions. Naive as i am, i thought that the llvm-bytecode is allways in SSA form. But this doesn't seem to be the case. At least there are no phi instructions embedded if the bytecode drops out of llvm-gcc? Looking into the archives this has been discussed before:

# Front matter # First, I want to emphasize that this is not a short-term plan. This is a long-term plan. When I was looking at refactoring the existing Alias Analysis infrastructure in LLVM in ways that would break stateful AA, Hal Finkel asked me to figure out how things would work with the new pass manager and make sure that was sane. This plan assumes the new pass manager. There is nothing