search for: fp_inc

Hi, I'm working now on extending SCEV Analysis and adding FP support. At the beginning, I want to vectorize this loop: float fp_inc; float x = init; for (int i=0;i<N;i++){ A[i] = x; x += fp_inc; // Loop invariant variable or constant } In this loop "x" is a FP induction variable. But it is not the "primary" induction and loop trip count is still depends on integer induction "i"....

> On May 16, 2016, at 5:35 PM, Hal Finkel via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > ----- Original Message ----- >> From: "Sanjoy Das via llvm-dev" <llvm-dev at lists.llvm.org> >> To: escha at apple.com >> Cc: "llvm-dev" <llvm-dev at lists.llvm.org>, "Michael V Zolotukhin" <michael.v.zolotukhin at

...on relevant workloads without teaching SCEV about floating point values at all. > > Are there conceivable use cases for this infrastructure beyond vectorizing a small subcategory of loops of this form? > > float x = init; > for (int i=0;i<N;i++){ > A[i] = x; > x += fp_inc; // Loop invariant variable or constant > } > > Can the vectorizer handle loops of this form without querying SCEV? > > SCEV expressions have an inherent width. They are not infinite precision. This is the main challenge of working with SCEV expressions, as Sanjoy is well aware. W...

...without teaching SCEV about floating point values at all. > > > > Are there conceivable use cases for this infrastructure beyond vectorizing > a small subcategory of loops of this form? > > > > float x = init; > for (int i=0;i<N;i++){ > A[i] = x; > x += fp_inc; // Loop invariant variable or constant > } > > > > Can the vectorizer handle loops of this form without querying SCEV? > > > > SCEV expressions have an inherent width. They are not infinite precision. > This is the main challenge of working with SCEV expressions, as...