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Register Allocation Pref. in 3.3.3
- From: "Paulo J. Matos" <pocmatos at gmail dot com>
- To: gcc at gcc dot gnu dot org
- Date: Mon, 22 Feb 2010 10:45:17 +0000
- Subject: Register Allocation Pref. in 3.3.3
Hi,
For anyone who still remembers what went on with 3.3.3, in global.c,
set_preference, why is there a bias to set preference for operand 0 of
src?
It is not intuitive and I there's no comment regarding this so I guess
there is some 'assumption' gcc makes regarding the order of operands.
Two generic questions regarding this version:
- Does the order in which define_insn and define_expand rules show up
in the .md file bias the compiler to choose a rule in one way or the
other?
- If two define_insn patterns match the same insn, which one will be used?
Cheers,
--
PMatos