similar to: [LLVMdev] CaptureTracking.h?

If there are any students looking for ideas, here a couple of projects you might consider. p.s. Anyone know where in the repo the OpenProjects page is? I'd expected it to be the docs/ folder of the LLVM repo, but it wasn't. Transactional Memory Optimization Intel recently introduced transactional memory support in hardware. This project would consist of implementing optimizations

Hi Philip, > On Mar 22, 2016, at 4:43 PM, Philip Reames via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > If there are any students looking for ideas, here a couple of projects you might consider. > > p.s. Anyone know where in the repo the OpenProjects page is? I'd expected it to be the docs/ folder of the LLVM repo, but it wasn't. Is it what you're

Working on a downstream optimization which uses CaptureTracking (CT) I came across a coupling problem. It looks like optimizations and analyses which use CT often need to be in sync with CT implementation. Analyzing the uses of the given pointer CT handles three kinds of uses: * Simple non-capturing use. When one is encountered, CT just moves on. * Non-capturing, but produces another value,

Eh? How do you envision this? -eric On Tue, Jun 17, 2014 at 2:09 PM, Jingyue Wu <jingyue at google.com> wrote: > Hi Nick, > > That makes sense. I think a main issue here is that the ranges of these PTX > special registers (e.g., threadIdx.x) depend on -target-cpu which is only > visible to clang and llc. Would you mind we specify "target cpu" in the IR > similar

On 17 June 2014 06:41, Eli Bendersky <eliben at google.com> wrote: > On Tue, Jun 17, 2014 at 1:38 AM, Nick Lewycky <nicholas at mxc.ca> wrote: > >> Chandler Carruth wrote: >> >>> This seems fine to me, but I'd like to make sure it looks OK to Nick as >>> well. >>> >> >> I strongly prefer baking in knowledge about the

On Tue, Jun 17, 2014 at 2:33 PM, Jingyue Wu <jingyue at google.com> wrote: > Hi Eric, > > In the IR, besides "target datalayout" and "target triple", we have a > special "target cpu" string which is set by the Clang front-end according to > its -target-cpu flag. We also write a Module::getTargetCPU() method to > retrieve this string from the

Hi, The range metadata can only be attached to LoadInst for now. I am considering extending its usage to IntrinsicInst so that the frontend can annotate the range of the return value of an intrinsic call. e.g., %a = call i32 @llvm.xxx(), !range !0 !0 = metadata !{ i32 0, i23 1024 } The motivation behind this extension is some optimizations we are working on for CUDA programs. Some special

Chandler Carruth wrote: > This seems fine to me, but I'd like to make sure it looks OK to Nick as > well. I strongly prefer baking in knowledge about the intrinsics themselves into the passes if possible. Metadata will always be secondary. Separately, should value tracking look use range metadata when it's available? Absolutely. I think it should apply to all CallInst not just

PR43308 describes a case where StackProtector fails to protect against a fairly simple smash. This problem started after r363169, which removed StackProtector's own analysis function HasAddressTaken, and used CaptureTracking's PointerMayBeCaptured instead. The problem here is that "pointer is captured" and "pointer could be used to smash the stack" are not equivalent

Hello, As I can see, recently LLVM switched to using assume bundles to encode alignment information: https://reviews.llvm.org/rG78de7297abe2e8fa782682168989c70e3cb34a5c However, it seems that the ValueTracking cannot understand the new format. As an example, consider compilation of the following reproducer with clang-11 (old assume format) and clang-trunk (assume bundles): #include

Some optimizations depend on whether alloca instruction always has non-zero value. Currently, this checking is done by isKnownNonZero() in ValueTracking, and it assumes alloca in address space 0 always has non-zero value but alloca in non-zero address spaces does not always have non-zero value. However, this assumption is incorrect for certain targets. For example, amdgcn---amdgiz target has

Hi there lowering experts, Can the llvm.mem* intrinsics ever turn into a library call? Or do they invariably turn into inline code? This comes up because there was a patch to StackProtector to use CaptureTracking instead of a home-grown analysis, which changes the treatment of calls to intrinsics. (The old code treated them as normal calls, the new code decides intrinsics can never capture.)

Hal, Thanks for your suggestion. I think that makes sense. Currently, non-zero alloca address space is already represented by data layout, e.g., the last component of the data layout of amdgcn---amdgiz target is -A5, which means alloca is in address space 5. How about adding a letter z to -A5 to indicate alloca may have zero value? i.e. -A5 means alloca is in address space 5 and always has

Hello, This simple patch fixes PR9112: Index: lib/Analysis/ValueTracking.cpp =================================================================== --- lib/Analysis/ValueTracking.cpp (revision 125281) +++ lib/Analysis/ValueTracking.cpp (working copy) @@ -593,6 +593,8 @@ // Otherwise take the unions of the known bit sets of the operands, // taking conservative care to avoid

Hi everyone, I posted some questions related to implementing inference of nsw/nuw flags based on known icmp results to Bug 30428 ( https://llvm.org/bugs/show_bug.cgi?id=30428 ) and it was recommended that I engage a wider audience by coming here. The minimal context is the following, please see the bug report for more detail: > 1. If (X s< Y), then both X + 1 and Y - 1 are nsw. > 2.

>> I realise that the DataTypes.h.in part might be controversial. Also, >> there's probably a better place to put it, but I'm not sure where. > > I didn't apply this part. What problems does it cause to not have > this? Can we fix uses of max and min? I get these errors in lib: .../lib/Analysis/ValueTracking.cpp:162: error: no matching function for call to

Hi all, I came across an issue caused by the Call-Graph Simplify Pass. Here is a a small repro: ``` define double @foo(double %a1, double %a2, double %a3) #0 { entry: %a_mul = fmul double %a1, %a2 %a_cmp = fcmp ogt double %a3, %a_mul br i1 %a_cmp, label %a.then, label %a.end a.then: %a_div = fdiv double %a_mul, %a3 br label %a.end a.end: %a_factor = phi double [ %a_div, %a.then ],

[+current llvm-dev address] On 03/15/2017 09:23 AM, Hal Finkel wrote: > Hi Samuel, > > What are you taking about? ;) > > The only way to get a SIGFPE from a floating-point division by zero is > to modify the floating-point environment to enable those exceptions. > We don't support that (*). In the default (supported) environment, > floating point division is well

Eric Christopher wrote: > How are you trying to call it? Do you have a DataLayout? In test/Analysis/ValueTracking/memory-dereferenceable.ll, just change byval to dereferenceable(8), and %dparam won't match (see lib/IR/Value.cpp:521 for the logic that is supposed to fire). How do I get it to pass? I tried introducing a target-triple and target-datalayout, but it didn't help.

It’s true, I am working on this. I have committed the initial patch to add constrained intrinsics for the basic FP operations. This has the desired effect of preventing optimizations that would violate strict FP semantics with regard to rounding mode and exception status, but it also prevents many safe optimizations. Later this year I’ll be going through the code base and trying to teach