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The architecture has many comparison instructions, including some that extend one of the operands. The signed comparison instructions use sign extensions and the unsigned comparison instructions use zero extensions. In cases where we had a free choice between signed or unsigned comparisons, we were trying to decide at lowering time which would best fit the available instructions, taking things like extension type into account. The code to do that was getting increasingly hairy and was also making some bad decisions. E.g. when comparing the result of two LLCs, it is better to use CR rather than CLR, since CR can be fused with a branch while CLR can't. This patch removes the lowering code and instead adds an operand to integer comparisons to say whether signed comparison is required, whether unsigned comparison is required, or whether either is OK. We can then leave the choice of instruction up to the normal isel code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190138 91177308-0d34-0410-b5e6-96231b3b80d8
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