similar to: [LLVMdev] getTripCount requires which optimization passes?

hi, On Fri, May 7, 2010 at 8:59 AM, Trevor Harmon <Trevor.W.Harmon at nasa.gov>wrote: > Hi, > > For me, getTripCount always returns null, even for trivial loops such > as: > > void simple(int j) { > for (int i = 0; i < 10; i++) { > j++; > } > } > > Looking through the mailing list archive, it appears that getTripCount > requires

On May 6, 2010, at 6:32 PM, ether zhhb wrote: > As the comment said: > /// The IndVarSimplify pass transforms loops to have a form that > this > /// function easily understands. > > you could try -indvars. After adding -indvars to the opt command, getTripCount still returns null. I suppose it's possible, depending on the scheduling of the pass manager, that

On May 7, 2010, at 11:17 AM, Trevor Harmon wrote: > On May 6, 2010, at 6:32 PM, ether zhhb wrote: > >> As the comment said: >> /// The IndVarSimplify pass transforms loops to have a form that >> this >> /// function easily understands. >> >> you could try -indvars. > > After adding -indvars to the opt command, getTripCount still returns

On May 10, 2010, at 11:45 AM, Dan Gohman wrote: > just make your front-ends add -indvars before > adding your pass. Sorry, I don't have a clue how to do this, and I can't find any docs about it. I'm using llvm-gcc; how can I tell it to add a pass? Trevor

Hello, I'm writing a new function pass, and I'm having trouble with getTripCount() in Loop. If I generate the bitcode for the test code with no optimization then getTripCount() returns NULL, but if I pass - O3 to the front-end then getTripCount() returns fine. My phase calls addRequiredID(LoopSimplifyID) from getAnalysisUsage() and I also tried putting -mem2reg at the front

I now understand that IndVarSimplify.cpp is capable of reproducing array references when the pointer initialization from the array address is found inside the immediately enclosing loop, such that in the following code: int A[20000], B[100], Z; int main() { int i, j, *a, *b; for ( a = &A[0], i = 0; i != 200; i++ ) for ( b = &B[0], j = 0; j != 100; j++

Hi, I am trying to add a new loop pass in which I making a call to get the trip count of the loop using Value *TripCountValue = L->getTripCount() However I am always getting NULL for TripCountValue (confirmed through gdb). I am running this pass after the canonicalization of induction variables: opt --debug-pass=Structure -stats -indvars -loop-rotate -my-loop-pass < main.bc >

Hi, I am trying to modify a loop by reducing the loop trip count from N to N-1 where N may be constant. I looked into using getTripCount[1] but discovered that this method returns a Value* which is N itself. This prevents me from using this method for changing the loop. I suggest creating another method for returning the 'cmp' instruction. The new getTripCount implementation will use the

Thanks a lot for your guys' help!!! I guess once I am able to get *V* (which probably is a pointer to a Value object), then, I can instrument some code at the IR level to dump V. As long as I maintain V at this pass stage, I should be able to dump the loop trip count. This is true, isn't it? Basically, what I am going to do is to add a function call before the loop body, such as:

On Thu, 28 Jul 2005, Naftali Schwartz wrote: > I now understand that IndVarSimplify.cpp is capable of reproducing array > references when the pointer initialization from the array address is found > inside the immediately enclosing loop, such that in the following code: Ok. > int A[20000], B[100], Z; > int main() > { > int i, j, *a, *b; > for ( a =

Prakash Prabhu wrote: > I am trying to add a new loop pass in which I making a call to get the > trip count of the loop using > > Value *TripCountValue = L->getTripCount() That should work. Could you file a bug and attach the bytecode after 'opt -indvars -loop-rotate'? I would need that to determine why LoopInfo::getTripCount isn't returning any value. Nick

I found out that Loop::getTripCount method is obsolete in LLVM 3.1 Is there an alternative? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20120702/ea6ca4e6/attachment.html>

Sorry, I could not the the loop trip count with getTripCount(). I used a simple program as a test case: ------------------------------------------------------ #include <stdio.h> int getV(int i) { return i * 2; } int main() { int num = 10; int sum=0; int i; for (i=0; i<num; i++) { sum += getV(i); } return 0;

Hello, I'm having some trouble with getTripCount() ... again. In particular it fails in the first of the following two examples, although it works for the second. By fails, I mean it returns NULL. ---------- example 1 ---------- test1(int *a, const int *ip) { int k; for (k = 0; k < ip[2]; ++k) { a[k] = (k+11)/(k+2); } } ---------- example 2 ---------- test2(int

Hi Taemin, On 03/07/2012 01:53, Taemin Kim wrote: > I found out that Loop::getTripCount method is obsolete in LLVM 3.1 > Is there an alternative? I use getSmallConstantTripCount() to get loop trip counts using the ScalarEvolution analysis pass. See include/llvm/Analysis/ScalarEvolution.h for a detailed explanation. Ivan > > > _______________________________________________

Hi, Seems pass scalar-evolution+indvars fail to get the loop trip count of the following case: int foo(int x, int y, int lam[256], int alp[256]) { int i; int z = y; for (i = 255; i >= 0; i--) { z += x; lam[i] = alp[i]; } return z; } The final optimized ll code is : define i32 @foo(i32 %x, i32 %y, i32* %lam, i32* %alp) nounwind { entry: br label %bb bb:

Hi, InstCombine canonicalizes index operands (unless they are into struct types) to pointer size. The comment says: "If we are using a wider index than needed for this platform, shrink it to what we need. If narrower, sign-extend it to what we need. This explicit cast can make subsequent optimizations more obvious.". For our architecture, the canonicalization is a bit

On Jan 19, 2011, at 2:03 PM, Nick Lewycky wrote: > On 19 January 2011 13:01, Dan Gohman <gohman at apple.com> wrote: > > On Jan 18, 2011, at 12:32 AM, Nick Lewycky wrote: > > > Hi, > > > > I tracked down a bug in indvars where we weren't updating SCEV properly. The attached patch shows the fix to this bug with a testcase, but it also causes five new test

On 19 January 2011 13:01, Dan Gohman <gohman at apple.com> wrote: > > On Jan 18, 2011, at 12:32 AM, Nick Lewycky wrote: > > > Hi, > > > > I tracked down a bug in indvars where we weren't updating SCEV properly. > The attached patch shows the fix to this bug with a testcase, but it also > causes five new test failures. > > Indvars isn't

Hi, What's the proper way to abort a pass if something goes wrong (e.g., in the pass's constructor)? Do I simply call abort()? I looked through the existing passes but didn't see an example of this. Thanks, Trevor