WordIsSmi, by itself, is not that descriptive, as it just ands a word with the heap object tag. With this change, the MachineGraphVerifier can check that the input to TaggedIsSmi actually has a tagged representation.

This CL also introduces a few bitcast operators in the Smi* macros in the CodeStubAssembler.

R=bmeurer@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2407303002
Cr-Commit-Position: refs/heads/master@{#40209}