On Thu, 11 Aug 2011, Georg-Johann Lay wrote:
> This is an optimization in machine dependent reorg to > remove redundant comparisons like in > > cc0 = compare (Reg, Num) > if (cc0 == 0) > goto L1 > > cc0 = compare (Reg, Num) > if (cc0 > 0) > goto L2 > > The second comparison is redundant an can be removed. > Code like this can be seen in binary decision switch/case > expansion. A glance at AVR makes me think this should already be handled by the NOTICE_UPDATE_CC machinery. Any analysis why this doesn't happen? With the same test-case (at -Os) I don't see redundant compares for cris-elf, for example. brgds, H-P
