TARGET_SHIFT_TRUNCATION_MASK

[Paolo Bonzini]

On 07/15/2010 02:26 PM, Uros Bizjak wrote:
> The reason you pointed out is for SHIFT_COUNT_TRUNCATED. Please note,
> that we don't use memory_operands, but even in register operand case,
> "bt" insn doesn't truncate the bit-count operand, but performs modulo
> operation on it. I.E, "bt %reg, 75" will not return 0, but shift insn
> with the same operands will.

Yes, only for memory_operands.

You can take a look at the attached patch.  I never got round to finish 
it, but I think it bootstrapped.  It unifies SHIFT_COUNT_TRUNCATED and 
TARGET_SHIFT_TRUNCATION_MASK, I think it can be useful for x86.

Paolo
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