s390: SImode pointers vs LR
Andreas Krebbel
krebbel@linux.vnet.ibm.com
Wed Jun 3 07:07:00 GMT 2015
On 06/02/2015 07:13 PM, Jeff Law wrote:
> But isn't that 3 registers used in the address computation if the
> (const_int 1) gets reloaded? one of the value shifted, two for the
> shift count? I'm not familiar with the s390, so if you can handle that
> kind of insn, then, umm, cool.
The address style operand is only the shift count. Our instructions support base + displacement
here. E.g. sll %r2,%r3(3) is r2 << (r3 + 3)
> The only other thing that comes immediately to mind would be secondary
> reloads. But I always hate suggesting them.
I don't see how this would help here. It is not really that reload needs help moving something
to/from a register. In fact the INSN is good as is and we are trying to prevent reload from doing
anything.
Bye,
-Andreas-
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