testcase for recent dag combiner patch. Before the entry bb was:

_test:
        stwu r1, -80(r1)
        stw r1, 76(r1)
        mflr r11
        stw r11, 88(r1)
        rlwinm r2, r4, 0, 30, 31
        cmplwi cr7, r2, 2
        mfcr r2
        rlwinm r2, r2, 30, 31, 31
        cmplwi cr0, r2, 0
        bne cr0, LBB1_2 ;UnifiedReturnBlock

after it is:

_test:
        stwu r1, -80(r1)
        stw r1, 76(r1)
        mflr r11
        stw r11, 88(r1)
        rlwinm r2, r4, 0, 30, 31
        cmplwi cr0, r2, 2
        bgt cr0, LBB1_2 ;UnifiedReturnBlock

llvm-svn: 30954