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LLVM backend for 6502
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ad0124c188
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Chris Lattner ad0124c188 Enhance the shift-shift folding code to allow a no-op cast to occur in between 
the shifts.

This allows us to fold this (which is the 'integer add a constant' sequence
from cozmic's scheme compmiler):

int %x(uint %anf-temporary776) {
        %anf-temporary777 = shr uint %anf-temporary776, ubyte 1
        %anf-temporary800 = cast uint %anf-temporary777 to int
        %anf-temporary804 = shl int %anf-temporary800, ubyte 1
        %anf-temporary805 = add int %anf-temporary804, -2
        %anf-temporary806 = or int %anf-temporary805, 1
        ret int %anf-temporary806
}

into this:

int %x(uint %anf-temporary776) {
        %anf-temporary776 = cast uint %anf-temporary776 to int
        %anf-temporary776.mask1 = add int %anf-temporary776, -2
        %anf-temporary805 = or int %anf-temporary776.mask1, 1
        ret int %anf-temporary805
}

note that instcombine already knew how to eliminate the AND that the two
shifts fold into.  This is tested by InstCombine/shift.ll:test26

-Chris


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25128 91177308-0d34-0410-b5e6-96231b3b80d8
2006-01-06 07:52:12 +00:00
autoconf For PR678: 2005-12-22 02:08:30 +00:00
docs Added the spec for the new "extractelement" instruction. 2006-01-05 17:37:02 +00:00
examples
include/llvm Grammer correction. 2006-01-05 01:53:28 +00:00
lib Enhance the shift-shift folding code to allow a no-op cast to occur in between 2006-01-06 07:52:12 +00:00
projects
runtime
test A case that instcombine is not catching. 2006-01-06 07:48:28 +00:00
tools remove unused header 2006-01-05 00:21:37 +00:00
utils Tweak pattern complexity calc. 2006-01-06 02:30:23 +00:00
win32 Teach Visual Studio about new file. 2006-01-04 17:19:48 +00:00
Xcode Adding new files. 2006-01-04 13:37:32 +00:00
.cvsignore
configure Implement fix for PR471: 2005-12-21 03:31:53 +00:00
CREDITS.TXT credit where credit is due 2005-12-22 06:09:08 +00:00
LICENSE.TXT Happy New Year, LLVM. 2006-01-03 14:42:06 +00:00
llvm.spec
llvm.spec.in
Makefile
Makefile.common
Makefile.config.in Implement fix for PR471: 2005-12-21 03:31:53 +00:00
Makefile.rules For PR625: 2005-12-23 22:27:56 +00:00
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