[PATCH] D149421: [KnownBits] Improve `KnownBits::rem(X, Y)` in cases where we can deduce low-bits of output

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon accepted this revision.
RKSimon added a comment.
This revision is now accepted and ready to land.

LGTM with a minor



================
Comment at: llvm/lib/Support/KnownBits.cpp:568
     // The upper bits are all zero, the lower ones are unchanged.
+    // NB: Low bits set in `remGetLowBits`.
     APInt LowBits = RHS.getConstant() - 1;
----------------
// NB: Low one bits set in `remGetLowBits`


================
Comment at: llvm/lib/Support/KnownBits.cpp:588
     // The low bits of the first operand are unchanged by the srem.
+    // NB: Low bits set in `remGetLowBits`.
     APInt LowBits = RHS.getConstant() - 1;
----------------
// NB: Low one bits set in `remGetLowBits`


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  https://reviews.llvm.org/D149421/new/

https://reviews.llvm.org/D149421