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ad0124c188
llvm-6502/lib/Transforms
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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
..
Hello
Instrumentation
IPO Pull inline methods out of the pass class definition to make it easier to 2006-01-03 19:13:17 +00:00
Scalar Enhance the shift-shift folding code to allow a no-op cast to occur in between 2006-01-06 07:52:12 +00:00
Utils
ExprTypeConvert.cpp
LevelRaise.cpp
Makefile
TransformInternals.cpp
TransformInternals.h