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Re: RFA: -mfpmath=sse -fpic vs double constants
- From: Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: Dale Johannesen <dalej at apple dot com>
- Date: Fri, 08 Jul 2005 18:32:35 +0200
- Subject: Re: RFA: -mfpmath=sse -fpic vs double constants
- References: <fda4ff71b36df5e262502282c5c8ea55@apple.com> <42CE9DC9.1030708@lu.unisi.ch> <42CEA12B.6030001@lu.unisi.ch>
Like this; untested, but pretty obvious. Ok for mainline?
David Edelsohn disapproved this on IRC because PPC benefits from this
(also performance-wise).
It is possible to change compress_float_constant to do the change only
if {cost_of_load_single}+{cost_of_extend} <= {cost_of_load_double}.
Unfortunately a change to compress_float_constant needs auditing on all
targets that explicitly test the cost of FLOAT_EXTEND. These are:
- alpha
- i386
- mips
- rs6000, whose cost can be lowered to 0 for DFmode
- sparc
- vax, whose cost have to be checked anyway according to a comment.
Paolo