Bug 891739 - IonMonkey: Make or_ and xor_ range analysis even more precise, and avoid calling js_bitscan_clz32 with a zero operand. r=nbp,waldo
Backed out 3 changesets (bug 889480, bug 889788, bug 888908) for mochitest-bc orange.

Backed out changeset d1c616745325 (bug 889788)
Backed out changeset 6fe281a19554 (bug 888908)
Backed out changeset 9b855bab8073 (bug 889480)