search for: bolvanski

Displaying 20 results from an estimated 25 matches for "bolvanski".

Did you mean: bolvanský
2018 Apr 20
2
Missed strlen optimizations
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:
2018 Apr 20
0
Missed strlen optimizations
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
2018 May 22
0
DSE: Remove useless stores between malloc & memset
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,
2018 May 22
2
DSE: Remove useless stores between malloc & memset
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
2018 May 22
2
DSE: Remove useless stores between malloc & memset
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
2018 May 22
0
DSE: Remove useless stores between malloc & memset
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
2018 Apr 20
2
Missed strlen optimizations
Hello, Code: https://godbolt.org/g/EG4Wi6 unsigned fff3(void) { char buf[10] = ""; return strlen(buf); } Since we are memset-ing before strlen call, we could replace strlen with just 0. Has LLVM any API to get "last instruction before strlen" which modifies strlen argument "buf"? So we can check "yes, it is memset there, replace strlen
2018 Apr 20
0
Missed strlen optimizations
Is: 2018-04-20 18:07 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > Hello, > > Code: https://godbolt.org/g/EG4Wi6 > > unsigned fff3(void) { > char buf[10] = ""; > return strlen(buf); > } > > Since we are memset-ing before strlen call, we could replace strlen with > just 0. > > Has LLVM any API to get
2018 May 09
0
Ignored branch predictor hints
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 >>
2018 May 09
2
Ignored branch predictor hints
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
2018 May 09
3
Ignored branch predictor hints
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
2018 May 22
0
DSE: Remove useless stores between malloc & memset
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:
2018 May 22
2
DSE: Remove useless stores between malloc & memset
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
2018 Sep 16
2
[cfe-dev] New warnings when building trunk with GCC 9
Yes, we should produce this warning in C++11 mode too. (I could be misrecalling, but I think the rationale for the current behaviour is based on historical GCC behaviour.) On Sun, 16 Sep 2018, 10:04 David Blaikie via cfe-dev, < cfe-dev at lists.llvm.org> wrote: > Fair point made on that thread - that this is a DR, so technically the > std::move is pessimizing even in C++11 mode.
2018 May 22
2
DSE: Remove useless stores between malloc & memset
* 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* >
2018 Sep 15
2
New warnings when building trunk with GCC 9
There is a new discussion related to -Wredundant-move warning on GCC bugzilla. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87300 pi 14. 9. 2018 o 9:53 David Blaikie <dblaikie at gmail.com> napísal(a): > > > On Fri, Sep 14, 2018 at 12:48 AM Stephan Bergmann <sbergman at redhat.com> > wrote: > >> On 13/09/2018 18:22, David Blaikie via
2018 May 22
0
DSE: Remove useless stores between malloc & memset
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
2018 Sep 25
3
[cfe-dev] New warnings when building trunk with GCC 9
+ Erik, who implemented DR1579 Originally, I had the warning similar to GCC's warning, but took it out due to not having DR1579 implemented in clang (warning changed in r243594) Erik in r274291 implemented DR1579, although PR27785 didn't mention anything about std::move It looks like what's happening is that Clang and GCC handles the return differently. Clang needs the std::move
2018 Mar 09
0
Externally loadable Alias Analysis pass
I am currectly experimenting with -Xclang option.. I have a simple pass (to just print function names). I ran: clang -Xclang -load -Xclang LLVMHello.so t.c but nothing was printed, no output from the pass. when I run: opt -load LLVMHello.so -hello t.ll I get the output from pass (i.e. list of function names) Part of the source ode of the Hello pass: struct Hello : public FunctionPass {
2018 May 09
0
Ignored branch predictor hints
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) >