Handle constant addresses more efficiently, folding the low bits into the disp field of the load/store if possible.  This compiles CodeGen/PowerPC/load-constant-addr.ll to:
Handle constant addresses more efficiently, folding the low bits into the
disp field of the load/store if possible.  This compiles
CodeGen/PowerPC/load-constant-addr.ll to:

_test:
        lis r2, 2838
        lfs f1, 26848(r2)
        blr

instead of:

_test:
        lis r2, 2838
        ori r2, r2, 26848
        lfs f1, 0(r2)
        blr


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@26908 91177308-0d34-0410-b5e6-96231b3b80d8

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