similar to: Optimization: Replace functions with thread unsafe variants + detection of multithreading

Hello, I have a CallInstr for "functionA". I renamed it to "functionB" but I want to decrease number of arguments as functionA accepts e.g two and functionB just one. So far, I dont find any function to just replace args / set args size. Any idea? Maybe other solution... Is there any way to create a new CallInstr for functionB, copy things from CallInstr of functionB a copy

Hi, I'm trying to write a small piece of code that inlines all calls to a particular function. The codes is as follows Function* klee_check_divF = module->getFunction("klee_div_zero_check"); assert(klee_check_divF != 0 && "Failed to find klee_div_zero_check function"); // Hack inline checks for (Module::iterator f = module->begin(), fe =

Hi Bruce, thank you for your answer. What I want to know is following: Imagine that I create threads in some way. I want threads to execute the same BC, while using the same memory space. I know that LLVM IR has a nice structure: Context - Module - Execution engine. Is there a way to run several instances of LLVM (using threads for example) with the same memory space? On Fri, May 30, 2014 at

Use *last = nullptr; for (Use &U : Src->uses()) last = &U; last->getUser()->dump(); Or any better solution? 2018-04-20 19:19 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > Is: > > > 2018-04-20 18:07 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > >> Hello, >> >> Code: https://godbolt.org/g/EG4Wi6

Maybe nicer.. auto i = Src->uses().begin(); std::advance(i, Src->getNumUses() - 1); i->getUser()->dump(); 2018-04-20 19:19 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > Use *last = nullptr; > for (Use &U : Src->uses()) > last = &U; > last->getUser()->dump(); > > > Or any better solution? > > 2018-04-20 19:19

I just realised I forgot to reply to this. Thanks for advise, it's good to know. Thanks, Dan Liew. On 30 August 2013 16:25, David Blaikie <dblaikie at gmail.com> wrote: > On Fri, Aug 30, 2013 at 7:53 AM, Daniel Liew <daniel.liew at imperial.ac.uk> wrote: >> Hi, >> >> I'm trying to write a small piece of code that inlines all calls to a >> particular

You might want to look more carefully at how you're constructing the MemoryLocation.   The first argument is a pointer, and the second argument is the number of bytes pointed to by that pointer (or MemoryLocation::UnknownSize if the number of bytes accessed isn't known). More generally, copy-pasting code you don't understand isn't a good idea. -Eli On 5/22/2018 4:02 PM, Dávid

Yeah, sorry for that. Better "It compiles ok (but maybe incorrect code)", not "It works" as I wrote. 2018-05-23 1:08 GMT+02:00 Friedman, Eli <efriedma at codeaurora.org>: > You might want to look more carefully at how you're constructing the > MemoryLocation. The first argument is a pointer, and the second argument > is the number of bytes pointed to by

It works with MemoryLocation MemoryLocation::get(const CallInst *CI) { AAMDNodes AATags; CI->getAAMetadata(AATags); const auto &DL = CI->getModule()->getDataLayout(); return MemoryLocation(CI, DL.getTypeStoreSize(CI->getType()), AATags); } Is it fine? :) 2018-05-22 23:56 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > Looks like there are many overloads

Hi Dávid, Looks like you can defeat the switch conversion by adding a dummy asm(“”): #define likely(x) __builtin_expect((x),1) // switch like char * b(int e) { if (likely(e == 0)) return "0"; asm(""); if (e == 1) return "1"; else return "f"; } Dave > On May 9, 2018, at 2:33 PM, Dávid Bolvanský via llvm-dev

IR: define i32 @calloc_strlen_write_between() { %call = tail call noalias i8* @calloc(i32 10, i32 1) store i8 97, i8* %call, align 1 %call1 = tail call i32 @strlen(i8* %call) ret i32 %call1 } static bool eliminateStrlen(CallInst *CI, BasicBlock::iterator &BBI, AliasAnalysis *AA, MemoryDependenceResults *MD, const DataLayout &DL, const TargetLibraryInfo *TLI,

Full stack trace: opt: /home/xbolva00/LLVM/llvm/include/llvm/ADT/Optional.h:176: T* llvm::Optional<T>::getPointer() [with T = llvm::MemoryLocation]: Assertion `Storage.hasVal' failed. Stack dump: 0. Program arguments: opt aaa.ll -dse -S 1. Running pass 'Function Pass Manager' on module 'aaa.ll'. 2. Running pass 'Dead Store Elimination' on function

Looks like there are many overloads for "get". http://llvm.org/doxygen/MemoryLocation_8cpp_source.html But nothing for CallInst. Any suggestions how to do a proper one? I will look at it too. 2018-05-22 23:34 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > Full stack trace: > > opt: /home/xbolva00/LLVM/llvm/include/llvm/ADT/Optional.h:176: T* >

* if (isStringFromCalloc(Dst, TLI)) should be if (!isStringFromCalloc(Dst, TLI)) but still asserting... 2018-05-22 23:06 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > Can you help a bit? > > I try to work with DSE but I got the following assert: > opt: /home/xbolva00/LLVM/llvm/include/llvm/ADT/Optional.h:176: T* > llvm::Optional<T>::getPointer() [with T

I did https://bugs.llvm.org/show_bug.cgi?id=37368 2018-05-09 20:33 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > I did > > https://bugs.llvm.org/show_bug.cgi?id=37368 > > 2018-05-09 20:29 GMT+02:00 David Zarzycki <dave at znu.io>: > >> I’d wager that the if-else chain is being converted to a "switch >> statement” during an optimization

Hello, #define likely(x) __builtin_expect((x),1) // switch like char * b(int e) { if (likely(e == 0)) return "0"; else if (e == 1) return "1"; else return "f"; } GCC correctly prefers the first case: b(int): mov eax, OFFSET FLAT:.LC0 test edi, edi jne .L7 ret But Clang seems to ignore _builtin_expect hints in this case.

It looks like the memoryIsNotModifiedBetween assumes the second argument is a store, or some other instruction supported by MemoryLocation::get.  If you're passing in something else, you'll have to compute the MemoryLocation some other way. (Generally, if you're asking a question about an assertion, please include the whole stack trace; it's hard to guess what's happening

Thanks, interesting. But a fix needs to be made since branch predictor hints are broken in a valid C++20 code: https://godbolt.org/g/dpSDqd Dňa st 9. 5. 2018, 20:40 David Zarzycki <dave at znu.io> napísal(a): > Hi Dávid, > > Looks like you can defeat the switch conversion by adding a dummy asm(“”): > > #define likely(x) __builtin_expect((x),1) > > // switch like

memoryIsNotModifiedBetween is precisely the sort of expensive walk we shouldn't be doing... I'm surprised it hasn't caused any serious issues yet.  Ideally, what we should be doing is using MemorySSA to find a dependency from the memset: if the closest dependency is the malloc, there aren't any stores between the memset and the malloc.  (But we aren't using MemorySSA in

It could save useless parsing in s/f/printf during runtime. E.g. for heavy "fprint"ing code like fprintf(f, "%s: %s", TAG, msg); I think it could be quite useful. After this transformation we would get fprintf(f, "ABC: %s", msg); --> We could save one push/mov instruction + less parsing in printf every time we call it. We would just replace string constant