Paul S schrieb:
I've ported gcc to a 16 bit CPU and have all torture tests passing bar
one, pr52286.c
The offending lines of code are
long a, b = 0;
asm ("" : "=r" (a) : "0" (0));
which should cause zero to be assigned to the "a" SI sized variable.
Inspecting the generated code revealed t
On Mon, Aug 28, 2017 at 05:49:22PM -0600, Jeff Law wrote:
> Going back to pshortis issue, it's interesting how the size of the input
> operand is being used to determine the mode of the matching output
> operand. That ought to be not-too-difficult to find within GCC... With
> any luck there'd be
Hi,
On Mon, 28 Aug 2017, Jeff Law wrote:
> > asm ("" : "=r" (x) : "r" (y+z));
> > asm ("" : "=r" (x) : "r" (z));
> > asm ("" : "=r" (x) : "r" (42));
>
> >
> > (are we still agreeing on this? I'm having a problem understanding why
> > you think the above wouldn't work)
>
> How do we rep
On 08/28/2017 11:56 AM, Michael Matz wrote:
> Hi,
>
> On Mon, 28 Aug 2017, Jeff Law wrote:
>
>> I can't remember matching constraints ever working that way.
>
> They do work exactly so. These uses are all correct, though they place
> some random value into x:
Hmm, maybe I've spent too much tim
Thanks Michael (and Jeff)
I shared your view about the mode of the output register not
being reflected to the input until I saw
(asm_operands:SI ("") ("=r") 0 [
(reg:HI 30)
]
then I was unsure whether the input was affecting the output or
the output mode w
Hi,
On Mon, 28 Aug 2017, Michael Matz wrote:
> On Mon, 28 Aug 2017, Jeff Law wrote:
>
> > I can't remember matching constraints ever working that way.
>
> They do work exactly so.
FWIW, I was momentarily worried that there once was a world where you were
right. If so (and I don't believe it)
Hi,
On Mon, 28 Aug 2017, Paul S wrote:
> I've ported gcc to a 16 bit CPU and have all torture tests passing bar one,
> pr52286.c
>
> The offending lines of code are
>
> long a, b = 0;
> asm ("" : "=r" (a) : "0" (0));
>
>
> which should cause zero to be assigned to the "a" SI sized variabl
Hi,
On Mon, 28 Aug 2017, Jeff Law wrote:
> I can't remember matching constraints ever working that way.
They do work exactly so. These uses are all correct, though they place
some random value into x:
int x, y, z;
y = z = init();
asm ("" : "=r" (x) : "r" (y+z));
asm ("" : "=r" (x) : "
On 08/28/2017 11:33 AM, Michael Matz wrote:
> Hi,
>
> On Mon, 28 Aug 2017, Jeff Law wrote:
>
>>> long a, b = 0;
>>> asm ("" : "=r" (a) : "0" (0));
>> I wouldn't use a matching constraint here. Something like this is
>> probably closer to what you want:
>>
>> asm ("" : "=r" (a) : "n" (0));
>>
Hi,
On Mon, 28 Aug 2017, Jeff Law wrote:
> > long a, b = 0;
> > asm ("" : "=r" (a) : "0" (0));
> I wouldn't use a matching constraint here. Something like this is
> probably closer to what you want:
>
> asm ("" : "=r" (a) : "n" (0));
>
> The "n" says accept any immediate integer constant w
On 08/27/2017 09:33 PM, Paul S wrote:
> I've ported gcc to a 16 bit CPU and have all torture tests passing bar
> one, pr52286.c
>
> The offending lines of code are
>
> long a, b = 0;
> asm ("" : "=r" (a) : "0" (0));
I wouldn't use a matching constraint here. Something like this is
probably c
I've ported gcc to a 16 bit CPU and have all torture tests
passing bar one, pr52286.c
The offending lines of code are
long a, b = 0;
asm ("" : "=r" (a) : "0" (0));
which should cause zero to be assigned to the "a" SI sized variable.
Inspecting the generated code revealed that zero was on
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