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Re: Integer moves for fp regs
- To: law at cygnus dot com
- Subject: Re: Integer moves for fp regs
- From: Michael Hayes <michaelh at ongaonga dot chch dot cri dot nz>
- Date: Wed, 29 Jul 1998 21:39:01 GMT
- Cc: Michael Hayes <michaelh at ongaonga dot chch dot cri dot nz>, egcs at cygnus dot com, gcc2 at cygnus dot com
- References: <199807291052.KAA06384@ongaonga.chch.cri.nz><7419.901730908@hurl.cygnus.com>
Jeffrey A Law writes:
> I believe it is still necessary if HARD_REGNO_MODE_OK allows floating
> point registers to hold integer mode values.
Do you know which bits of GCC require this behaviour?
> ? I thought caller-save tried to build and recognize suitable load/store
> insns for each mode and if a particular mode didn't work it wouldn't
> use it.
Yes, it does this. However, if HARD_REGNO_MODE_OK allows both
floating point and integer modes of the same size for a register,
then caller save will use integer save/restore instructions.
For most architectures this is of no concern since the representation
of the bit pattern is not important.