[Beignet] [PATCH] Fix a HSW regression.

[Yang, Rong R]

slmoffset is used as dst in DWord logical instruction, such as shift.
In such instruction, dst register must larger than src register, change slmoffset to Word may have potential issue. So it better to use DWord.

-----Original Message-----
From: Zhigang Gong [mailto:zhigang.gong at linux.intel.com] 
Sent: Thursday, October 16, 2014 14:30
To: Yang, Rong R
Cc: beignet at lists.freedesktop.org
Subject: Re: [Beignet] [PATCH] Fix a HSW regression.

Good catch yang rong, but this doesn't look like a regression itself.
It has been there from the beginning. And considering that the total SLM size is only 64K, so a unsigned WORD should be good enough for it right?

We may need to fix the related code in the gen_insn_selection.cpp and gen75_context.cpp.

Last time I visited these special register allocations/definitions, I thought we lack of sanity check here and may allocate incorrect register space at backend which is very hard to debug.

We may need to add some sanity check between here and the actual special register allocation and usage places to make sure those registers are allocated correctly.

Any thought?


On Thu, Oct 16, 2014 at 11:07:37AM +0800, Yang Rong wrote:
> slmoffset use as DWORD register, but declare WORD, fix it.
> 
> Signed-off-by: Yang Rong <rong.r.yang at intel.com>
> ---
>  backend/src/ir/profile.cpp | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/backend/src/ir/profile.cpp b/backend/src/ir/profile.cpp 
> index 57cce4b..295b612 100644
> --- a/backend/src/ir/profile.cpp
> +++ b/backend/src/ir/profile.cpp
> @@ -83,7 +83,7 @@ namespace ir {
>        DECL_NEW_REG(FAMILY_DWORD, zero, 1);
>        DECL_NEW_REG(FAMILY_DWORD, one, 1);
>        DECL_NEW_REG(FAMILY_WORD, retVal, 1);
> -      DECL_NEW_REG(FAMILY_WORD, slmoffset, 1);
> +      DECL_NEW_REG(FAMILY_DWORD, slmoffset, 1);
>        DECL_NEW_REG(FAMILY_DWORD, printfbptr, 1);
>        DECL_NEW_REG(FAMILY_DWORD, printfiptr, 1);
>        DECL_NEW_REG(FAMILY_DWORD, invalid, 1);
> --
> 1.9.1
> 
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