On 05/27/2011 10:07 AM, Blue Swirl wrote:
>> The C99 hook exists to efficiently support targets that don't have
>> arithmetic shift operations. Honestly.
>
> So it would be impossible for a compiler developer to change the logic
> for shifts for some supported two's-complement logic CPUs (like x8
On Fri, May 27, 2011 at 12:14 AM, Richard Henderson wrote:
> On 05/26/2011 01:25 PM, Blue Swirl wrote:
>>> I don't see the point. The C99 implementation defined escape hatch
>>> exists for weird cpus. Which we won't be supporting as a QEMU host.
>>
>> Maybe not, but a compiler with this property
Richard Henderson wrote:
> On 05/26/2011 01:25 PM, Blue Swirl wrote:
> >> I don't see the point. The C99 implementation defined escape hatch
> >> exists for weird cpus. Which we won't be supporting as a QEMU host.
> >
> > Maybe not, but a compiler with this property could arrive. For
> > example
On 05/26/2011 09:14 PM, Blue Swirl wrote:
x = (int32_t)x>> (int32_t)y;
>>>
>> This expression has an implementation-defined behavior accroding to
>> C99 6.5.7 so we decided to emulate signed shifts by hand.
>
> Technically, yes. In practice, no. GCC, ICC, LLVM, MSVC all know
> what th
On 05/26/2011 01:25 PM, Blue Swirl wrote:
>> I don't see the point. The C99 implementation defined escape hatch
>> exists for weird cpus. Which we won't be supporting as a QEMU host.
>
> Maybe not, but a compiler with this property could arrive. For
> example, GCC developers could decide that si
On Thu, May 26, 2011 at 11:10 PM, Richard Henderson wrote:
> On 05/26/2011 12:14 PM, Blue Swirl wrote:
>> On Thu, May 26, 2011 at 4:56 PM, Richard Henderson wrote:
>>> On 05/26/2011 05:36 AM, Kirill Batuzov wrote:
> x = (int32_t)x >> (int32_t)y;
>
This expression has an implementat
On 05/26/2011 12:14 PM, Blue Swirl wrote:
> On Thu, May 26, 2011 at 4:56 PM, Richard Henderson wrote:
>> On 05/26/2011 05:36 AM, Kirill Batuzov wrote:
x = (int32_t)x >> (int32_t)y;
>>> This expression has an implementation-defined behavior accroding to
>>> C99 6.5.7 so we decided to em
On Thu, May 26, 2011 at 4:56 PM, Richard Henderson wrote:
> On 05/26/2011 05:36 AM, Kirill Batuzov wrote:
>>> x = (int32_t)x >> (int32_t)y;
>>>
>> This expression has an implementation-defined behavior accroding to
>> C99 6.5.7 so we decided to emulate signed shifts by hand.
>
> Technically, yes
On 05/26/2011 05:36 AM, Kirill Batuzov wrote:
>> x = (int32_t)x >> (int32_t)y;
>>
> This expression has an implementation-defined behavior accroding to
> C99 6.5.7 so we decided to emulate signed shifts by hand.
Technically, yes. In practice, no. GCC, ICC, LLVM, MSVC all know
what the user wan
On Fri, 20 May 2011, Richard Henderson wrote:
>
> On 05/20/2011 05:39 AM, Kirill Batuzov wrote:
> > +case INDEX_op_sar_i32:
> > +#if TCG_TARGET_REG_BITS == 64
> > +x &= 0x;
> > +y &= 0x;
> > +#endif
> > +r = x & 0x8000;
> > +x &= ~0x80
On 05/20/2011 05:39 AM, Kirill Batuzov wrote:
> +case INDEX_op_sar_i32:
> +#if TCG_TARGET_REG_BITS == 64
> +x &= 0x;
> +y &= 0x;
> +#endif
> +r = x & 0x8000;
> +x &= ~0x8000;
> +x >>= y;
> +r |= r - (r >> y);
> +x |
Perform constant forlding for SHR, SHL, SAR, ROTR, ROTL operations.
Signed-off-by: Kirill Batuzov
---
tcg/optimize.c | 87
1 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index a02d5c1..b6b
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