mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-02-19 06:31:18 +00:00
15d2c3fb00
This patch fixes the logic in the DAGCombiner that folds an AND node according to rule: (and (X (load V)), C) -> (X (load V)) An AND between a vector load 'X' and a constant build_vector 'C' can be folded into the load itself only if we can prove that the AND operation is redundant. The algorithm implemented by 'visitAND' firstly computes the splat value 'S' from C, and then checks if S has the lower 'B' bits set (where B is the size in bits of the vector element type). The algorithm takes into account also the 'undef' bits in the splat mask. Unfortunately, the algorithm only worked under the assumption that the size of S is a multiple of the vector element type. With this patch, we conservatively avoid folding the AND if the splat bits are not compatible with the vector element type. Added X86 test and-load-fold.ll Differential Revision: http://reviews.llvm.org/D8085 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231563 91177308-0d34-0410-b5e6-96231b3b80d8
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you're writing a package for LLVM, see docs/Packaging.rst for our suggestions.