Philip Reames 91a083c57f Carry facts about nullness and undef across GC relocation
This change implements four basic optimizations:

    If a relocated value isn't used, it doesn't need to be relocated.
    If the value being relocated is null, relocation doesn't change that. (Technically, this might be collector specific. I don't know of one which it doesn't work for though.)
    If the value being relocated is undef, the relocation is meaningless.
    If the value being relocated was known nonnull, the relocated pointer also isn't null. (Since it points to the same source language object.)

I outlined other planned work in comments.

Differential Revision: http://reviews.llvm.org/D6600



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224968 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-29 23:27:30 +00:00
2014-04-07 03:57:04 +00:00
2014-10-16 22:48:02 +00:00

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
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Please see the documentation provided in docs/ for further
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If you're writing a package for LLVM, see docs/Packaging.rst for our
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Description
LLVM backend for 6502
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