search for: anticonvergent

Hi all, LLVM needs a solution to the long-standing problem that the IR is unable to express certain semantics expected by high-level programming languages that target GPUs. Solving this issue is necessary both for upstream use of LLVM as a compiler backend for GPUs and for correctly supporting LLVM IR <-> SPIR-V roundtrip translation. It may also be useful for compilers targeting

...functions like > syncthreads(), to which we cannot add control-flow dependencies. > That is, it's legal to hoist syncthreads out of an "if", but it's > not legal to sink it into an "if".  It's not clear to me why we > can't have "anticonvergent" (terrible name) functions which cannot > have control-flow dependencies removed from them?  ballot() would be > both convergent and anticonvergent. > > Would that solve your problem? > > > I think it's important to note that we already have such an attr...

...> > syncthreads(), to which we cannot add control-flow dependencies. > > That is, it's legal to hoist syncthreads out of an "if", but it's > > not legal to sink it into an "if". It's not clear to me why we > > can't have "anticonvergent" (terrible name) functions which cannot > > have control-flow dependencies removed from them? ballot() would be > > both convergent and anticonvergent. > > > > Would that solve your problem? > > > > > > I think it's important to note that...

...ncthreads(), to which we cannot add control-flow dependencies. > > > That is, it's legal to hoist syncthreads out of an "if", but it's > > > not legal to sink it into an "if". It's not clear to me why we > > > can't have "anticonvergent" (terrible name) functions which cannot > > > have control-flow dependencies removed from them? ballot() would be > > > both convergent and anticonvergent. > > > > > > Would that solve your problem? > > > > > > > > > I th...

...which we cannot add control-flow dependencies. > > > > That is, it's legal to hoist syncthreads out of an "if", but it's > > > > not legal to sink it into an "if". It's not clear to me why we > > > > can't have "anticonvergent" (terrible name) functions which cannot > > > > have control-flow dependencies removed from them? ballot() would be > > > > both convergent and anticonvergent. > > > > > > > > Would that solve your problem? > > > > > >...

...control-flow dependencies. > > > > > That is, it's legal to hoist syncthreads out of an "if", but > it's > > > > > not legal to sink it into an "if". It's not clear to me why we > > > > > can't have "anticonvergent" (terrible name) functions which > cannot > > > > > have control-flow dependencies removed from them? ballot() > would be > > > > > both convergent and anticonvergent. > > > > > > > > > > Would that solve your problem?...

...control-flow dependencies. > > > > > That is, it's legal to hoist syncthreads out of an "if", but > it's > > > > > not legal to sink it into an "if". It's not clear to me why we > > > > > can't have "anticonvergent" (terrible name) functions which > cannot > > > > > have control-flow dependencies removed from them? ballot() > would be > > > > > both convergent and anticonvergent. > > > > > > > > > > Would that solve your problem?...

...control-flow dependencies. > > > > > That is, it's legal to hoist syncthreads out of an "if", but > it's > > > > > not legal to sink it into an "if". It's not clear to me why we > > > > > can't have "anticonvergent" (terrible name) functions which > cannot > > > > > have control-flow dependencies removed from them? ballot() > would be > > > > > both convergent and anticonvergent. > > > > > > > > > > Would that solve your problem?...

...> > > > >    That is, it's legal to hoist syncthreads out of an "if", > but it's > > > > >    not legal to sink it into an "if".  It's not clear to me > why we > > > > >    can't have "anticonvergent" (terrible name) functions > which cannot > > > > >    have control-flow dependencies removed from them? > ballot() would be > > > > >    both convergent and anticonvergent. > > > > > > > > > >    Wo...

...; > > That is, it's legal to hoist syncthreads out of an "if", > > but it's > > > > > > not legal to sink it into an "if". It's not clear to me > > why we > > > > > > can't have "anticonvergent" (terrible name) functions > > which cannot > > > > > > have control-flow dependencies removed from them? > > ballot() would be > > > > > > both convergent and anticonvergent. > > > > > > > >...