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Chris Lattner 079236d1c9 My faith in programmers has been found to be totally misplaced. One would
assume that if they don't intend to write to a global variable, that they
would mark it as constant.  However, there are people that don't understand
that the compiler can do nice things for them if they give it the information
it needs.

This pass looks for blatently obvious globals that are only ever read from.
Though it uses a trivially simple "alias analysis" of sorts, it is still able
to do amazing things to important benchmarks.  253.perlbmk, for example,
contains several ***GIANT*** function pointer tables that are not marked
constant and should be.  Marking them constant allows the optimizer to turn
a whole bunch of indirect calls into direct calls.  Note that only a link-time
optimizer can do this transformation, but perlbmk does have several strings
and other minor globals that can be marked constant by this pass when run
from GCCAS.

176.gcc has a ton of strings and large tables that are marked constant, both
at compile time (38 of them) and at link time (48 more).  Other benchmarks
give similar results, though it seems like big ones have disproportionally
more than small ones.

This pass is extremely quick and does good things.  I'm going to enable it
in gccas & gccld.  Not bad for 50 SLOC.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11836 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-25 21:34:36 +00:00
autoconf small portability fix. 2004-02-24 22:58:31 +00:00
docs Substantial improvements and cleanups for the release notes. We were missing 2004-02-25 16:36:51 +00:00
examples/ModuleMaker Configure script for ModuleMaker. 2003-11-25 20:02:07 +00:00
include Great renaming part II: Sparc --> SparcV9 (also includes command-line options and Makefiles) 2004-02-25 19:08:12 +00:00
lib My faith in programmers has been found to be totally misplaced. One would 2004-02-25 21:34:36 +00:00
projects Remove dependence on the return type of ConstantArray::get 2004-02-15 04:05:58 +00:00
runtime Build an archive for use with Povray. 2004-02-20 21:26:46 +00:00
test Note that this test is currently expected to fail. 2004-02-25 20:34:02 +00:00
tools Great renaming part II: Sparc --> SparcV9 (also includes command-line options and Makefiles) 2004-02-25 19:08:12 +00:00
utils Updated to use llc to generate CBE code. 2004-02-25 17:15:02 +00:00
.cvsignore Ok, try #2, this time I'll not be stupid 2003-08-03 18:33:24 +00:00
configure Added the VTune tests. 2004-02-24 21:43:38 +00:00
CREDITS.TXT Added Stacker to Reid Spencer's list of contributions. 2003-12-17 18:15:04 +00:00
LICENSE.TXT we no longer include boost 2004-02-24 04:02:20 +00:00
llvm.spec RPM spec file for LLVM tools and libraries. 2004-02-10 03:57:51 +00:00
llvm.spec.in RPM spec file for LLVM tools and libraries. 2004-02-10 03:57:51 +00:00
Makefile Should fix pr220 - "make install" doesn't install header files when 2004-02-10 01:10:01 +00:00
Makefile.common Added LLVM copyright notice. 2003-10-21 14:33:46 +00:00
Makefile.config.in Added the POVRAY_ROOT to locate Povray. 2004-02-20 22:30:46 +00:00
Makefile.rules Define DEPRECATED so that it can be used in function and variable 2004-02-13 20:05:44 +00:00
README.txt Merged in RELEASE_1. 2003-10-27 18:02:06 +00:00

                       The LLVM Compiler Infrastructure
                           http://llvm.cs.uiuc.edu

Welcome to LLVM!
----------------
This file is intended to do four things:
(1) help you get started using LLVM;
(2) tell you how to get questions about LLVM answered;
(3) tell you where to find documentation for different kinds of questions; and
(4) tell you about three LLVM-related mailing lists.


Getting Started with LLVM
-------------------------

(1) For license information:
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(2) Installing and compiling LLVM:
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(3) Learn about features and limitations of this release:
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(4) Learn how to write a pass within the LLVM system:
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(5) Learn how to start a new development project using LLVM, where your
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Getting Help with LLVM
----------------------

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LLVM Documentation
------------------

All the documents mentioned below except the design overview tech report
are included as part of the LLVM release (in llvm/docs/*):

LLVM Design Overview:
    LLVM : A Compilation Framework for Lifelong Program Analysis
    and Transformation:
        http://llvm.cs.uiuc.edu/pubs/2003-09-30-LifelongOptimizationTR.html

LLVM User Guides:

    Download and Installation Instructions:
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    LLVM Command Guide:
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LLVM Programming Documentation:

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    Alias Analysis in LLVM:
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    Command Line Library:
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Other LLVM Resources:

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