similar to: [LLVMdev] compare two GEP instructions operand by operand

Hi, I want to print the memory locations computed by getelementptr. As I understood, getelementptr does not access the memory, but it contains the address it computes. I want to print these addresses at runtime (or process them). So, I try to build a function that takes as argument a pointer and prints its value. And to call this function, by sending the gep instruction as a parameter.

On 7/20/11 10:02 AM, Jimborean Alexandra wrote: > Hi, > > I want to print the memory locations computed by getelementptr. As I > understood, getelementptr does not access the memory, but it contains > the address it computes. I want to print these addresses at runtime > (or process them). So, I try to build a function that takes as > argument a pointer and prints its

Hello, How can I compute the functions on the loop iterators used as array indices?  For example: for i = 0, N       for j = 0, M             A[2*i + j - 10] = ...  Can I obtain that this instruction A[2*i + j - 10]= .. always accesses memory using a function       f(i,j)   =   2*i + j - 10 + base_address_of_A If I run the scalar evolution pass on this code I obtain: %arrayidx =

Hi again, Thank you, your suggestion worked well. I was looking for a pointer to void actually. But it seems that I do not get the memory address when passing the value of the GEP instruction.  For instance, when I print the address accessed by the second operandof the store instruction store %struct.linked* %tmp23.reload8, %struct.linked** %curr.037.reg2mem I obtain a memory address of the

Hello Tobi, You are right, we need to run some other passes before running the scalar evolution pass. The sequence that I run for this example is -O3 -loop-simplify -reg2mem.  This is why I did not obtain the expressions depending on the loop indices. So I removed the reg2mem pass and scalar evolution computes the correct functions. However, I need to run the reg2mem pass (or any other that

On 07/27/2011 03:11 PM, Jimborean Alexandra wrote: > Hello, > > How can I compute the functions on the loop iterators used as array > indices? > > For example: > > for i = 0, N > for j = 0, M > A[2*i + j - 10] = ... > > Can I obtain that this instruction A[2*i + j - 10]= .. always accesses > memory using a function f(i,j) = 2*i + j - 10 + base_address_of_A

Hi Renato, No, I cannot, but in case it is, I want to take advantage of this. In case it is not, the instrumentation code will detect this at runtime and simply roll back to the original version. I will always keep an original version available, in addition to the ones I modify with Polly. However, initially I will speculate that it is allocated contiguously. Thanks, Alexandra

Only because in my next passes I change the CFG significantly and it is very hard to maintain the values of the Phi nodes. Alexandra ________________________________ From: Tobias Grosser <tobias at grosser.es> To: Jimborean Alexandra <xinfinity_a at yahoo.com> Cc: "llvmdev at cs.uiuc.edu" <llvmdev at cs.uiuc.edu>; "luismastrangelo at gmail.com"

Hello, Can anyone please guide me how can I replace a load instruction with a prefetch. I was looking at the intrinsic creation methods of the IRBuilder, but I can only find functions corresponding to memset, memcpy and memmove intrinsics, not for prefetching. Also, I target x86-64 architectures. Is it sufficient to insert a call to the intrinsic in the LLVM IR to have the corresponding prefetch

Hi Tobi, Thank you for your reply :). I know that array accesses are handled as pointers in LLVM, but as I understood Polly is focused on statically analysable code. As you mentioned: proving that pointer accesses actually represent virtual array accesses. In the case of a linked list for example, parsed with a pointer p = p->next, I expect that Polly will not handle this code. So I

Alexandra, I'm not sure what you mean by "replace", but I have code that does this to insert prefetches: Type *I8Ptr = Type::getInt8PtrTy((*I)->getContext(), PtrAddrSpace); Value *PrefPtrValue = ... IRBuilder<> Builder(MemI); Module *M = (*I)->getParent()->getParent(); Type *I32 = Type::getInt32Ty((*I)->getContext()); Value

Hi, I would like to force the minimum number of bits allocated for a variable in memory to be 16. From what I have seen, i1 is already represented on 8 bits. So, the only change would be to represent i1 and i8 on 16 bits, as all other types already fulfill this condition. TargetData can help by setting a higher alignment, thus although the type is i1 or i8, the number of allocated bits is 16.

On 19 July 2011 10:12, Jimborean Alexandra <xinfinity_a at yahoo.com> wrote: > %curr_array = alloca [10 x %struct.linked], align 8 > > while.. >  %tmp16 = getelementptr inbounds [10 x %struct.linked]* %curr_array, i32 0, > i32 1 Hi Alexandra, Can you guarantee that the linked list will be allocated in contiguous memory? cheers, --renato

Hi Alexandra, I'm not sure want you want to do. Is the data layout string (http://llvm.org/docs/LangRef.html#datalayout, also usually set by each target specific *TargetMachine constructor), for setting the alignment good enough for you? Or is it more than the alignment you want to control? Do you have a target with 16-bit bytes? In that case, there is quite a lot of changes that needs to be

On 07/19/2011 11:46 AM, Jimborean Alexandra wrote: > Hi Renato, > > No, I cannot, but in case it is, I want to take advantage of this. In > case it is not, the instrumentation code will detect this at runtime and > simply roll back to the original version. I will always keep an original > version available, in addition to the ones I modify with Polly. However, > initially I

On 08/03/2011 08:35 AM, Jimborean Alexandra wrote: > Hello Tobi, > > You are right, we need to run some other passes before running the > scalar evolution pass. The sequence that I run for this example is -O3 > -loop-simplify -reg2mem. This is why I did not obtain the expressions > depending on the loop indices. So I removed the reg2mem pass and scalar > evolution computes the

On 08/03/2011 10:22 AM, Jimborean Alexandra wrote: > Only because in my next passes I change the CFG significantly and it is > very hard to maintain the values of the Phi nodes. OK. In Polly we developed a pass called, 'independent-blocks-pass'. It basically creates basic blocks, that can easily be rescheduled without stopping the scalar evolution analysis to work. Maybe something

Hi, I plan to do some speculative parallelization in LLVM using Polly and I target loops that contain pointers and indirect references. As far as I know, Polly generates optimized code starting from the SCoPs, therefore I plan to replace all pointer accesses with array accesses, such that Polly will accept the code. Each array access should use a liner function of the enclosing loops indices.

Hi, I want to execute the iterations of a loop in parallel, by inserting calls either to pthreads or to the gomp library at the LLVM IR level. As a first step, I inserted an omp pragma in a C file and compiled it with llvm-gcc to check the generated LLVM code. If I understand correctly, to parallelize the loop in LLVM IR, I have to separate the loop in a new function, put all required parameters

Hi, I try to write a FunctionPass that, among other tasks, has to clone some loops from the current function. How can I obtain the LPPassManager in order to use the CloneLoop function. In a LoopPass this is a parameter for the runOnLoop, but how can I obtain it in a FunctionPass? I tried simply by creating a new instance : ValueMap<const Value *, Value* > VMap;