[LLVMdev] vectorize a def-use chain (original) (raw)

Jason thesurprises at gmail.com
Wed Jul 8 15:48:38 PDT 2015

Two ways I've done this:

  1. Create a ReplaceAllUsesWithUnsafe() function that does the same as ReplaceAllUsesWith except without the check for compatible types, knowing that eventually you will end up with a fully compatible instruction eventually.
  2. Do a recursive traversal up the use-def chain from the store back through all the args. This will ensure that at every instruction, all the args will have been vectorized through the recursion, and all you really need to do at that point is call Instruction::mutateType() to ensure the return type of the instruction matches the vector args.

Thanks Jason

On Wed, Jul 8, 2015 at 3:18 PM, Frank Winter <fwinter at jlab.org> wrote:

I'd like to replace scalar instructions with vector instructions such that the code corresponding to following tree would be vectorized:

load0 load1 \ / \ / add/sub/mul | | store I had unsuccessful encounters with load0->replaceAllUsesWith(vecload0) complaining about mismatching type (makes sense, add's other operand is still scalar at that time..) Is the only way to create a vectorized version of this tree by 1) creating the vector loads vecload0 AND vecload1 2) retrieving the opcode of the arithmetic instruction and create a new one according to the opcode How is step 2) in donepractice? Cloning the instruction and replacing the operands? (would that bypass the type checking for a moment?) Thanks, Frank

LLVM Developers mailing list LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150708/4b747382/attachment.html>

More information about the llvm-dev mailing list