[PATCH] D32339: [APInt] Add compare/compareSigned methods that return -1, 0, 1. Reimplement slt/ult and friends using them

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.

Currently sle and ule have to call slt/ult and eq to get the proper answer. This results in extra code for both calls and additional scans of multiword APInts.

This patch replaces slt/ult with a compareSigned/compare that can return -1, 0, or 1 so we can cover all the comparison functions with a single call.

While I was there I removed the activeBits calls and other checks at the start of the slow part of ult. Both of the activeBits calls potentially scan through each of the APInts separately. I can't imagine that's any better than just scanning them in parallel and doing the compares.

These changes seem to be good for about a 7-8k reduction on the size of the opt binary on my local x86-64 build.


https://reviews.llvm.org/D32339

Files:
  include/llvm/ADT/APInt.h
  lib/Support/APInt.cpp

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