[PATCH] D34029: Infer lowest bits of an integer Multiply when the low bits of the operands are known

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: lib/Analysis/ValueTracking.cpp:377
+  unsigned ResultBitsKnown = std::min(TrailBitsKnown0 - TrailZero0,
+                                      TrailBitsKnown1 - TrailZero1);
+  // We know at least the trailing zeros, plus any other known bits
----------------
Reusing the name ResultBitsKnown is confusing.


================
Comment at: lib/Analysis/ValueTracking.cpp:380
+  // of the operands.
+  ResultBitsKnown = std::min(ResultBitsKnown + TrailZ, BitWidth);
+
----------------
These little comments aren't that useful for understanding the logic; needs one big paragraph explaining the logic for computing ResultBitsKnown.


https://reviews.llvm.org/D34029