Evgeniy Stepanov 4031b194ac [msan] Do not store origin for clean values.
Instead of unconditionally storing origin with every application store,
only do this when the shadow of the stored value is != 0.

This change also delays instrumentation of stores until after the walk over
function's instructions, because adding new basic blocks confuses InstVisitor.

We only keep 1 origin value per 4 bytes of application memory. This change
fixes the bug when a store of a single clean byte wiped the origin for the
whole 4-byte area.

Since stores of uninitialized values are relatively uncommon, this change
improves performance of track-origins mode by 5% median and by up to 47% on
specs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169490 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-06 11:41:03 +00:00
2012-11-19 19:31:02 +00:00
2012-12-06 07:38:10 +00:00
2012-10-09 23:48:34 +00:00
2012-11-19 19:31:02 +00:00
2012-11-29 21:17:26 +00:00
2012-11-14 22:13:56 +00:00
2012-11-29 16:19:11 +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
the license agreement found in LICENSE.txt.

Please see the HTML documentation provided in docs/index.html for further
assistance with LLVM.

If you're writing a package for LLVM, see docs/Packaging.html for our
suggestions.
Description
LLVM backend for 6502
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