search for: inductionvariables

LLVM, What is the status of the InductionVariable "semi-pass"? I have tested it out on spec benchmarks, and while it does correctly identify some of the variables, it fails to recognize most. Typically the following scenario arises a_loop: ... %tmp.19 = load int* %bsLive %tmp.20 = add int %tmp.19, -8 store int %tmp.20, int* %bsLive %tmp.5 = setgt int %tmp.20, 0 br bool %tmp.5, label

Hello LLVM, Can you suggest a good way to use the loops and induction variable passes to map loop exiting BasicBlocks to InductionVariables. That is, can we use these tools to identify the loop condition. What i have tried Function Pass: foreach BB if(terminal is loop exit of containing loop) trace back to instruction producing the cond that the branch branches on - condProducer foreach(inst in loop header)...

> Can you suggest a good way to use the loops and induction variable > passes to map loop exiting BasicBlocks to InductionVariables. That is, > can we use these tools to identify the loop condition. I can try. :) It looks like you're running into problems because we don't perform "Linear Function Test Replacement". This optimization would reduce the amount of code which occurs between the induction var...

Hi all, I've started looking at the GlobalMerge pass, enabled by default on ARM and AArch64. I think we should reconsider that, at least for AArch64. As is, the pass just merges all globals together, in groups of 4KB (AArch64, 128B on ARM). At the time it was enabled, the general thinking was "it's almost free, it doesn't affect performance much, we might as well use it".

Hi, I'm working on project which involves writing a backend for a hypothetical architecture. I am currently trying to figure out the best way to translate for loops to use a specialized "loop" instruction the architecture supports. The instruction is similar X86's loop instruction, where a register is automatically decremented and the condition is automatically checked to see if

Hello, I was interested in how much Type-Based Alias Analysis helps to optimize code. For that purpose, I've compared three sets of benchmarks: compiled without TBAA, compiled with a default TBAA metadata format, and compiled with new TBAA metadata format. As a set of benchmarks, I've used the LLVM test suite (http://llvm.org/docs/TestingGuide.html#test-suite-overview) which has a lot of

tl;dr in low data situations we don’t look at past information, and that increases the false positive regression rate. We should look at the possibly incorrect recent past runs to fix that. Motivation: LNT’s current regression detection system has false positive rate that is too high to make it useful. With test suites as large as the llvm “test-suite” a single report will show hundreds of

Hi Chris and others! I totally support any work in this direction. In the current state LNT’s regression detection system is too noisy, which makes it almost impossible to use in some cases. If after each run a developer gets a dozen of ‘regressions’, none of which happens to be real, he/she won’t care about such reports after a while. We clearly need to filter out as much noise as we can - and

Hi, Sean: I'm sorry I lie. I didn't mean to lie. I did try to avoid making a *BIG* change to the IPO pass-ordering for now. However, when I make a minor change to populateLTOPassManager() by separating module-pass and non-module-passes, I saw quite a few performance difference, most of them are degradations. Attacking these degradations one by one in a piecemeal manner is wasting

Andy and I briefly discussed this the other day, we have not yet got chance to list a detailed pass order for the pre- and post- IPO scalar optimizations. This is wish-list in our mind: pre-IPO: based on the ordering he propose, get rid of the inlining (or just inline tiny func), get rid of all loop xforms... post-IPO: get rid of inlining, or maybe we still need it, only