similar to: question about mem2reg

Hi all! While playing with LLVM, I've found a weird behavior in mem2reg pass. When optimizing single stores, undefined value is placed before any load preceding the store (based on basicblock's ordering and simple dominator analysis, if I remember correctly). This is the line that is responsible for the behavior: (LLVM9 does the same)

Hi, Does LLVM have java frontend which can change Java bytecode to LLVM IR? Thanks a lot! Best, Linhai -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160112/1d9c0c7b/attachment.html>

Hello everyone, I am writing a pass to instrument program and count how many basic block executed. What I have tried is to instrument a local counter inside each function, add 1 to the local counter inside each basic block, and save the counter value to a global counter. The current runtime overhead is around 25%. Is there any way I can try to lower the overhead? Like keeping the local counter

Hi John, Thanks a lot for the reply! I try mem2reg opt and also implement the algorithm proposed in "Efficiently Counting Program Events with Support for On-line Queries" to place the local counter smarter. If I build the executable by using -O0, the overhead would be 20% - 30%. But if I build the executable by using -O2, the overhead would be more than 3X. I feel instrumenting counter

Hi everyone: The code I am analyzing is : int main() { int i = 0; printf("hello world!"); printf( "%d" , i ); } I want to get each place where printf is called, and the argument used during that call. so I write llvm pass code like: void Myfunction( Function & F){ for( Function::iterator b = F.begin() , be = F.end() ;

On 1/26/18 1:04 AM, Linhai Song via llvm-dev wrote: > > Hello everyone, > > > I am writing a pass to instrument program and count how many basic > block executed. What I have tried is to instrument a local counter > inside each function, add 1 to the local counter inside each basic > block, and save the counter value to a global counter. The current > runtime

> On 1/26/11 2:40 PM, songlh at cs.wisc.edu wrote: >> thanks! >> >> After I check the ll file, I find this: >> >> %1 = load %struct.nsAString** %aBuf_addr, align 4, !dbg !2048 >> %2 = getelementptr inbounds %struct.nsAString* %1, i32 0, i32 0, !dbg >> !2048 >> %3 = getelementptr inbounds %struct.nsISupports* %2, i32 0, i32 0, !dbg >> !2048

Hi, I am wondering whether the latest llvm-gcc version is 4.2. This is the latest version I can find on llvm web site. Thanks a lot! Best, Linhai

Hi, I am wondering whether there are some ways I can tell clang not inline some or all functions. Thanks a lot! Linhai

Hi, I just notice that front-end will add an extra block for switch instruction without default. How could I identify basic blocks added due to this reason? The added codes looks like: sw.default.i625: ; preds = %if.end512 tail call void @fancy_abort(i8* getelementptr inbounds ([38 x i8]* @.str, i64 0, i64 0), i32 3045, i8* getelementptr inbounds

> On 1/26/11 3:00 PM, songlh at cs.wisc.edu wrote: >>> On 1/26/11 2:40 PM, songlh at cs.wisc.edu wrote: >>>> thanks! >>>> >>>> After I check the ll file, I find this: >>>> >>>> %1 = load %struct.nsAString** %aBuf_addr, align 4, !dbg !2048 >>>> %2 = getelementptr inbounds %struct.nsAString* %1, i32 0, i32 0, !dbg

----- Original Message ----- > From: "Jingyue Wu" <jingyue at google.com> > To: "songlh" <songlh at cs.wisc.edu>, llvmdev at cs.uiuc.edu > Sent: Wednesday, October 15, 2014 2:50:12 PM > Subject: Re: [LLVMdev] how to choose which alias analysis used in my pass? > > > Isn't -basicaa the default alias analysis already? No, -basicaa is added

On 1/26/11 3:00 PM, songlh at cs.wisc.edu wrote: >> On 1/26/11 2:40 PM, songlh at cs.wisc.edu wrote: >>> thanks! >>> >>> After I check the ll file, I find this: >>> >>> %1 = load %struct.nsAString** %aBuf_addr, align 4, !dbg !2048 >>> %2 = getelementptr inbounds %struct.nsAString* %1, i32 0, i32 0, !dbg >>> !2048 >>> %3

I'm seeing the following fail on Linux x86-64, for the last couple weeks at least. This is from 'ninja check-all'. -David FAIL: lld :: wasm/function-index.test (1941 of 1955) ******************** TEST 'lld :: wasm/function-index.test' FAILED ******************** Script: -- : 'RUN: at line 1'; /build/x86_64/bin/llc -filetype=obj

Hi, all, I think I found a bug on mem2reg in a particular case. When I ran opt -mem2reg -basicaa -scalar-evolution -loops -da -analyze opts.ll, it collapsed. While without mem2reg option, it runs well. so I guess it has something to do with mem2reg. The relative files have been affixed, please check them for me. Thanks in advance. liubaosen at tsinghua.edu.cn -------------- next part

Well, 'optnone' is already not identical to -O0, and given the nature of things, probably can't be; but I am persuaded that it's reasonable for it to honor the -fast-isel option as a debugging tactic. I'll take an AI to make this happen. Thanks, --paulr P.S. One nit, the "O0 + optnone" case should not have an asterisk, the FastISel flag is not manipulated if the opt

In D28404, Mehdi wanted to use the 'optnone' attribute as a way to record "I was compiled with -O0" in the IR, because it seems like a good idea to remember that fact in an LTO compilation and there is no way to remember that fact currently. A couple of people felt it might be better to have this idea discussed on the dev list, where it might get better exposure, so I'm

> > The other thing that might work, is having TargetMachine remember how > > the fast-isel option got set, and make OptLevelChanger do the right > > thing. But that seems like a hack to work around Mips not obeying the > > specified optimization level, honestly. > > I think we should do that as well. I don't think it's right that optnone > enables Fast

----- Original Message ----- > From: "Ashutosh Nema" <Ashutosh.Nema at amd.com> > To: "songlh" <songlh at cs.wisc.edu>, llvmdev at cs.uiuc.edu > Sent: Wednesday, February 11, 2015 3:20:27 AM > Subject: Re: [LLVMdev] question about licm > > Hi, > > LICM can only hoist instructions which dominates all loop exit > blocks. > In this case

On Wed, Jun 21, 2017 at 05:25:04PM -0700, Mehdi AMINI via llvm-dev wrote: > Hi Kuba, > > Try: > > __attribute__(optnone) > > See > https://clang.llvm.org/docs/AttributeReference.html#optnone-clang-optnone Actually, it should be enough to use: __attribute__((noinline)) void please_do_not_optimize_me_away(int arg1, void *arg2) { asm