[PATCH] Teach ComputeNumSignBits about signed divisions

[Sanjoy Das]

REPOSITORY
  rL LLVM

================
Comment at: lib/Analysis/ValueTracking.cpp:1732
@@ +1731,3 @@
+
+      // Ignore non-positivie denominator.
+      if (!Denominator->isStrictlyPositive())
----------------
Nit: "non-positive"

================
Comment at: lib/Analysis/ValueTracking.cpp:1733
@@ +1732,3 @@
+      // Ignore non-positivie denominator.
+      if (!Denominator->isStrictlyPositive())
+        break;
----------------
Why not do this check before the call to `ComputeNumSignBits`?  Then we'll bail out earlier without doing unnecessary work.

http://reviews.llvm.org/D8028

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