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Re: -mfused-madd vs -ffp-contract deprication?

On 11/08/2010 02:58 PM, Joseph S. Myers wrote:
> <>:
> Existing target options may sometimes be ambiguous as to whether they are 
> meant to disable instructions that might not be available, or to disable 
> automatic conversion

It's currently used in:


Given that MIPS doesn't implement true FMA, MIPS probably should
match the (plus (mult a b) c) pattern unconditionally (modulo ISA)
and be done with it.

The rest of the targets either have the instructions in the base
ISA (xtensa, s390, rs6000, ia64) or additionally have some other
macro that controls availability (i386).

So, if we fix MIPS all remaining users will only control contraction.
Only xtensa has not been converted to the named fma patterns, though
many still contain additional (plus (mult)) patterns for FUSED_MADD.
Given that we have a pass that performs that operation at the tree
level, it would seem that all we need to do is delete the obsolete


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