[Bug target/52412] another unnecessary register move on arm

[amker.cheng at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52412

amker.cheng <amker.cheng at gmail dot com> changed:

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--- Comment #2 from amker.cheng <amker.cheng at gmail dot com> 2012-07-31 14:12:54 UTC ---
The register move insn is generated by cse2 pass, and after that, there is no
cprop pass till ira.
The two allocnos for r6/r3(the original pseudos) are conflict with each other,
though they contains same value and connected by move insn, IRA cannot allocate
same hard register for them.
Moveover, the case is compile with Os, where gcc does IRA in whole single
region, and live range cannot be split either.