================ @@ -0,0 +1,839 @@ +//===- AArch64LoopIdiomTransform.cpp - Loop idiom recognition -------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This pass implements a pass that recognizes certain loop idioms and +// transforms them into more optimized versions of the same loop. In cases +// where this happens, it can be a significant performance win. +// +// We currently only recognize one loop that finds the first mismatched byte +// in an array and returns the index, i.e. something like: +// +// while (++i != n) { +// if (a[i] != b[i]) +// break; +// } +// +// In this example we can actually vectorize the loop despite the early exit, +// although the loop vectorizer does not support it. It requires some extra +// checks to deal with the possibility of faulting loads when crossing page +// boundaries. However, even with these checks it is still profitable to do the +// transformation. +// +//===----------------------------------------------------------------------===// +// +// TODO List: +// +// * When optimizing for code size we may want to avoid some transformations. ---------------- davemgreen wrote:
Can we add a check for this now? It looks like it will be quite a bit bigger? https://github.com/llvm/llvm-project/pull/72273 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
