On ia32 allow powers of two and corresponding full bit masks as safe smis.
On ia32 allow powers of two and corresponding full bit masks as safe smis.

This considerably improves generated code allowing these values (commonly used in bitwise computations) to be embedded as immediates.

R=fschneider@google.com
BUG=

Review URL: https://codereview.chromium.org//490023004

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@39449 260f80e4-7a28-3924-810f-c04153c831b5

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