similar to: [LLVMdev] Possible issue with DenseMap when using AliasSetTracker

Oliver Horst wrote: > Dear All, > > while willing to assist developers to adhere strictly to coding guidelines, I > wrote the attached program called "alias-detector". The program's intent is to > utilize the BasicAliasAnalysis to get a list of aliases for each pointer in a > certain program code. First it initializes clang as frontend, executes the >

Quoting Eli Friedman <eli.friedman at gmail.com>: Dear Eli, Thanks very much for your reply. I have modified the XX and YY to be global variables, but the output of AliasSetTracker are still MUST alias: Alias Set Tracker: 5 alias sets for 4 pointer values. AliasSet[0xea55d0,0] may alias, Mod/Ref 8 Call Sites: void ({ }*)* @llvm.dbg.func.start, void (i32, i32, { }*)*

On Thu, May 7, 2009 at 5:07 PM, <hc2428 at columbia.edu> wrote: > However, I am a little confused with these output. In Both anders-aa > and steens-aa, XX and YY should stay in the same AliasSet, and their > alias relationship should be May Alias, right? %XX and %YY are the results of alloca instructions (i.e. equivalent to the C expressions "&XX" and

Dear Staff, Here are some questions on the output formats of AliasSetTracker. The code is as below: int G1 = 9; int G2 = 5; int main() { int * XX; int * YY; XX = &G1; YY = XX; YY = &G2; XX = &G2; } The output for -anders-aa is: Alias Set Tracker: 5 alias sets for 4 pointer values. AliasSet[0xea6fb0,0] may alias, Mod/Ref 10 Call Sites: void ({ }*)*

Hi all, There is a problem about how AliasSetTracker merging AliasSet's when meet UnknownInst. When adding new pointer it looks for existing AliasSet's aliased with new pointer. And merging them together. It is ok for pointers: if %A mayalias %B and %B mayalias %C then %A mayalias %C. But the same logic when adding callsite is wrong ( findAliasSetForUnknownInst). Callsite may be known

I started using the AliasSetTracker, but I have a problem. I am using -basicaa -anders-aa and optimizations are enabled for llvm-gcc and llvm-ld. I use an instruction visitor to populate the alias set tracker, but two pointers end up in different alias sets. While investigating this I notice at one point that if I call: bool New = false; AliasSet &X = AST->getAliasSetForPointer(Pointer,

On Aug 17, 2009, at 4:16 PM, Marcus Hicks wrote: > I started using the AliasSetTracker, but I have a problem. Hi Marcus, At best, anders-aa is beta-quality. It probably has several bugs and is not really ready to be widely used. -Chris > > I am using -basicaa -anders-aa and optimizations are enabled for > llvm-gcc and llvm-ld. > I use an instruction visitor to populate the

Dear Staff, Here are some questions on the output formats of AliasSetTracker. The code is as below: int G1 = 9; int G2 = 5; int main() { int * XX; int * YY; XX = &G1; YY = XX; YY = &G2; XX = &G2; } The output for -anders-aa is (the command is: opt -anders-aa test.bc -disable-output -print-alias-sets &>

On 01/27/2016 07:53 AM, Daniel Berlin wrote: > > > On Wed, Jan 27, 2016 at 1:27 AM, Roman Gareev <gareevroman at gmail.com > <mailto:gareevroman at gmail.com>> wrote: > > Thank you for the idea! Could you please explain it? > > > Which part are you having trouble with, so i know where to concetrate? > > If I’m not > mistaken, you advise

Thank you for the idea! Could you please explain it? If I’m not mistaken, you advise to insert the unknown insts of an every AS from AliasSetTracker::add(const AliasSetTracker &AST) into a smallptrset and consequently append it to merged alias sets from AliasSetTracker::findAliasSetForUnknownInst. I think that Philip proposed something similar to your approach in

Dear llvm contributors, Could you please advise me how to skip checks, which are performed in AliasSet::aliasesUnknownInst, of unknown instructions from different alias sets of an alias set tracker that is a parameter of ‘AliasSetTracker::add(const AliasSetTracker &AST)’? If this wasn’t available at the moment and someone could review me, I would try to implement it. A temporary patch can be

2015-12-11 23:44 GMT+05:00 Hal Finkel <hfinkel at anl.gov>: > Hi Roman, > > The MemoryLocation objects are involved in findAliasSetForUnknownInst, but none are created there for the memset intrinsic. MemoryLocation objects are only involved for the regular memory accesses being compared to the unknown instruction. See AliasSet::aliasesUnknownInst in lib/Analysis/AliasSetTracker.cpp.

Hello, I got a strange result when I used alias analysis DSAA, can you tell what is wrong? 1. The following is the primary body of my pass "fps.cpp": AliasAnalysis *AA = &getAnalysis<AliasAnalysis>(); AliasSetTracker AST(*AA); for (Module::iterator fi = M.begin(), fe = M.end(); fi != fe; ++fi ) for (Function::iterator bi = fi->begin(), be = fi->end(); bi

Oh, your meaning is pointers in a aliasset have equal address logically? But I think that two pointers are alias means they point to a same memory object, so if pointers "p" and "q" are alias, it seem as p = q, not &p = &q. Another question is about "forwarding". "AliasSet[XXXX, 0] may alias, Mod/Ref forwarding to YYYY" (XXXX != YYYY) means the

Thank you, Chris. The following is my comprehension about the AliasSetTracker, please correct me. 1. A aliasset "as" represents a memory object, and all pointer "p" in "as" represent values with the type of pointer that may/must point to the memory object "as". 2. If a aliasset is "forwarding", it has been merged to another aliasset and I

Hi again! Replying in chronological order: > On Thu, Jul 9, 2020 at 6:51 PM Shuai Wang <wangshuai901 at gmail.com > <mailto:wangshuai901 at gmail.com>> wrote: > > Hey Matt, > > That's awesome. Thank you very much for all the information and > clarification! Just a few follow up questions. Could you kindly shed > some lights on it? Thank

On Thu, Jan 15, 2015 at 1:26 PM, Nick Lewycky <nlewycky at google.com> wrote: > On 15 January 2015 at 13:10, Daniel Berlin <dberlin at dberlin.org> wrote: > >> Yes. >> I've attached an updated patch that does the following: >> >> 1. Fixes the partialalias of globals/arguments >> 2. Enables partialalias for cases where nothing has been unified to

Hi, I have the following C loop to vectorize: struct box { double* source; }; void test(double* restrict result, struct box my_struct, int len) { for (int i=0 ; i<len; i++) { result[i] = my_struct.source[i] * my_struct.source[i]; } } There are two references in the loop, result[i] (restrict) and my_struct.source[i] (readonly). The compiler should easily figure out that

Hi Danny, // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that // BasicAliasAnalysis wins if they disagree. This is intended to help // support "obvious" type-punning idioms. - if (UseCFLAA) - addPass(createCFLAliasAnalysisPass()); addPass(createTypeBasedAliasAnalysisPass()); addPass(createScopedNoAliasAAPass()); + if (UseCFLAA) +

Hi! On 7/10/2020 07:17, Shuai Wang wrote: > Hello! > > Thank you very much! Yes, that makes a lot of sense to me. However, just > want to point out two things that are still unclear: > > 1. The output contains a alias set of only one element, for instance: > "must alias, Mod       Pointers: (i32* %y, LocationSize::precise(4))" > > This one really confused