Turn HCompareHoleAndBranch into a HUnaryControlInstruction.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/24195009

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16805 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Move NumberToStringStub::GenerateLookupNumberStringCache to the MacroAssembler.

This renames the method to LookupNumberStringCache() and puts it into
the MacroAssembler in preparation of the NumberToStringStub Hydrogen
conversion.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/23618056

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16806 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Add HLoadRoot hydrogen instruction.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/23601038

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16807 ce2b1a6d-e550-0410-aec6-3dcde31c8c00