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Several architectures use the same instruction to perform both a comparison and a subtract. The instruction selection framework does not allow to consider different basic blocks to expose such fusion opportunities. Therefore, these instructions are “merged” by CSE at MI IR level. To increase the likelihood of CSE to apply in such situation, we reorder the operands of the comparison, when they have the same complexity, so that they matches the order of the most frequent subtract. E.g., icmp A, B ... sub B, A <rdar://problem/14514580> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190352 91177308-0d34-0410-b5e6-96231b3b80d8
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