[PATCH] D38536: Improve lookThroughCast function.

[Sanjay Patel via Phabricator via llvm-commits]

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

LGTM - see inline notes for a couple of changes to the code comments.



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Comment at: lib/Analysis/ValueTracking.cpp:4312
+/// 2. As restored constant (by applying reverse cast operation) when the first
+/// value of the inital "select" is a cast operation and the second value is a
+/// constant.
----------------
typo: initial - you could just remove that word, and the comment would be better.


================
Comment at: lib/Analysis/ValueTracking.cpp:4350-4355
+      //   %c = cmp iN %x, a
+      //   %t = trunc iN %y to iK
+      //   %sel = select i1 %c, iK %t, iK b
+      //
+      // where a and b are constants. We can always move trunc after select
+      // operation:
----------------
It's more typical to use 'C' for constant values in code and comments in LLVM, so I'd change this comment text and formula to match the code:
  %cond = cmp iN %x, CmpConst
  %tr = trunc iN %x to iK
  %narrowsel = select i1 %cond, iK %t, iK C
  -->
  %cond = cmp iN %x, CmpConst
  %widesel = select i1 %cond, iN %x, iN CmpConst
  %tr = trunc iN %widesel to iK


https://reviews.llvm.org/D38536