forked from OSchip/llvm-project
d67e463901
This adds a ScalarEvolution-powered transformation that updates load, store and memory intrinsic pointer alignments based on invariant((a+q) & b == 0) expressions. Many of the simple cases we can get with ValueTracking, but we still need something like this for the more complicated cases (such as those with an offset) that require some algebra. Note that gcc's __builtin_assume_aligned's optional third argument provides exactly for this kind of 'misalignment' offset for which this kind of logic is necessary. The primary motivation is to fixup alignments for vector loads/stores after vectorization (and unrolling). This pass is added to the optimization pipeline just after the SLP vectorizer runs (which, admittedly, does not preserve SE, although I imagine it could). Regardless, I actually don't think that the preservation matters too much in this case: SE computes lazily, and this pass won't issue any SE queries unless there are any assume intrinsics, so there should be no real additional cost in the common case (SLP does preserve DT and LoopInfo). llvm-svn: 217344 |
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| llvm.spec.in | ||
README.txt
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for the Low Level Virtual Machine, 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.