search for: vector_faddsub

...n. 2. Add an additional LLVM instruction. 3. Add a number of target-specific special cases into the higher-level code. I am not sure which is better, but I'd prefer to stay away from choice (3) as much as practical in favor of one of the first two options. Would you support adding some kind of vector_faddsub LLVM instruction? Also, there is a precedent, in some sense, for choices (1) and (2) in how fneg %a is serialized (as fsub -0.0, %a). Perhaps we could recognize fadd (fmul <-1.0, 1.0>), %b and turn it into something else for instruction selection in a similar way. -Hal > Dan > --...

...nstruction. > 3. Add a number of target-specific special cases into the higher-level > code. > > I am not sure which is better, but I'd prefer to stay away from choice > (3) as much as practical in favor of one of the first two options. Would > you support adding some kind of vector_faddsub LLVM instruction? I assume you mean an operator that subtracts even elements and adds odd elements; correct me if I'm wrong. I agree that this operation is fairly common; I think a general intrinsic to do this would be useful for people working on such targets. > > Also, there is a pr...

...number of target-specific special cases into the higher-level > > code. > > > > I am not sure which is better, but I'd prefer to stay away from choice > > (3) as much as practical in favor of one of the first two options. Would > > you support adding some kind of vector_faddsub LLVM instruction? > > I assume you mean an operator that subtracts even elements and adds odd > elements; correct me if I'm wrong. I agree that this operation is fairly > common; I think a general intrinsic to do this would be useful for people > working on such targets. Yes,...

On Oct 17, 2011, at 3:40 PM, Hal Finkel wrote: > How should I go about matching floating-point addsub-like vector > instructions? My first inclination is to write something which matches > build_vector 1.0, -1.0, and then use that in combination with a match on > fadd, but that does not seem to work. I think this is because > BUILD_VECTOR cannot ever be "Legal", and so it

How should I go about matching floating-point addsub-like vector instructions? My first inclination is to write something which matches build_vector 1.0, -1.0, and then use that in combination with a match on fadd, but that does not seem to work. I think this is because BUILD_VECTOR cannot ever be "Legal", and so it is always turned into a constant load before instruction selection.