https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105624
rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |rsandifo at gcc dot gnu.org
--- Comment #5 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org>
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FWIW, I think the problem is specific to operands that are
commutative with a non-constant operand. For example,
suppose the pre-RA instruction had a pseudo register R matching
a register_operand and a constant C matching a const_int_operand.
If R does not get allocated, and so gets replaced by a stack slot M,
the % would allow the RA to try mapping C to the register_operand
and M to the const_int_operand. Without a constraint on the latter,
the M mapping would seem to be valid, and reloading C into a register
might seem less costly than reloading M into a register.
The intent of the patch seemed good otherwise (and a nice clean-up).
I don't think the whole thing needed to be reverted.
