[Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
The llvm TGSI backend does things like:
LOAD TEMP[0].y, MEMORY[0]., TEMP[0].x
Expecting the data at address TEMP[0].x to get loaded to
TEMP[0].y. Before this commit the data at TEMP[0].x + 4 would be
loaded instead. This commit fixes this.
Signed-off-by: Hans de Goede
---
src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp | 8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
index 557608e..cc51f5a 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
@@ -2279,12 +2279,16 @@ Converter::handleLOAD(Value *dst0[4])
Value *off = fetchSrc(1, c);
Symbol *sym;
+ uint32_t src0_component_offset = tgsi.getSrc(0).getSwizzle(c) * 4;
+
if (tgsi.getSrc(1).getFile() == TGSI_FILE_IMMEDIATE) {
off = NULL;
sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
- tgsi.getSrc(1).getValueU32(0, info) + 4 * c);
+ tgsi.getSrc(1).getValueU32(0, info) +
+ src0_component_offset);
} else {
-sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c, 4 * c);
+sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
+ src0_component_offset);
}
Instruction *ld = mkLoad(TYPE_U32, dst0[c], sym, off);
--
2.7.3
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Re: [Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
That's wrong. The spec for the instruction needs to be clarified...
The current nouveau impl is correct - only the .x of the address
should be loaded, with up to 16 bytes read into the destination.
On Thu, Apr 7, 2016 at 9:27 AM, Hans de Goede wrote:
> The llvm TGSI backend does things like:
>
> LOAD TEMP[0].y, MEMORY[0]., TEMP[0].x
>
> Expecting the data at address TEMP[0].x to get loaded to
> TEMP[0].y. Before this commit the data at TEMP[0].x + 4 would be
> loaded instead. This commit fixes this.
>
> Signed-off-by: Hans de Goede
> ---
> src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp | 8 ++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> index 557608e..cc51f5a 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> @@ -2279,12 +2279,16 @@ Converter::handleLOAD(Value *dst0[4])
>
> Value *off = fetchSrc(1, c);
> Symbol *sym;
> + uint32_t src0_component_offset = tgsi.getSrc(0).getSwizzle(c) * 4;
> +
> if (tgsi.getSrc(1).getFile() == TGSI_FILE_IMMEDIATE) {
> off = NULL;
> sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
> - tgsi.getSrc(1).getValueU32(0, info) + 4 * c);
> + tgsi.getSrc(1).getValueU32(0, info) +
> + src0_component_offset);
> } else {
> -sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c, 4 * c);
> +sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
> + src0_component_offset);
> }
>
> Instruction *ld = mkLoad(TYPE_U32, dst0[c], sym, off);
> --
> 2.7.3
>
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Re: [Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
Hi,
On 07-04-16 15:58, Ilia Mirkin wrote:
That's wrong.
It used to work with the old RES[] code and if one cannot specify
a source swizzle, then how can I do something like
LOAD TEMP[0].y, MEMORY[0], address
And get the data at absolute global memory address "address" into TEMP[0].y ?
This is a must-have for llvm to be able to generate working TGSI code,
I do not see any way around this.
AFAIK this is exactly what src-swizzling is for. Also note that
this commit does not change anything if no src-swizzling is specified,
in that case things work exactly as before.
> The spec for the instruction needs to be clarified...
The current nouveau impl is correct - only the .x of the address
should be loaded, with up to 16 bytes read into the destination.
Ah note this is not about swizzling on the address, that indeed
makes no sense given how the addressing works for BUFFERS / MEMORY,
no this is about adding a swizlling postfix to the buffer / memory
resource specification, for example:
LOAD TEMP[0].y, MEMORY[0]., TEMP[0]
See the swizzling is done on the resource, not on the address, so
the swizzling specifies swizzling of the up to 16 bytes read from
address, it does not influence the address handling at all.
I now see I made an error in my commit msg, it gives the following
example:
LOAD TEMP[0].y, MEMORY[0]., TEMP[0].x
This clearly is wrong, the last TEMP[0].x is not even valid TGSI,
the correct example would be:
LOAD TEMP[0].y, MEMORY[0]., TEMP[0]
Regards,
Hans
On Thu, Apr 7, 2016 at 9:27 AM, Hans de Goede wrote:
The llvm TGSI backend does things like:
Expecting the data at address TEMP[0].x to get loaded to
TEMP[0].y. Before this commit the data at TEMP[0].x + 4 would be
loaded instead. This commit fixes this.
Signed-off-by: Hans de Goede
---
src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp | 8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
index 557608e..cc51f5a 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
@@ -2279,12 +2279,16 @@ Converter::handleLOAD(Value *dst0[4])
Value *off = fetchSrc(1, c);
Symbol *sym;
+ uint32_t src0_component_offset = tgsi.getSrc(0).getSwizzle(c) * 4;
+
if (tgsi.getSrc(1).getFile() == TGSI_FILE_IMMEDIATE) {
off = NULL;
sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
- tgsi.getSrc(1).getValueU32(0, info) + 4 * c);
+ tgsi.getSrc(1).getValueU32(0, info) +
+ src0_component_offset);
} else {
-sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c, 4 * c);
+sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
+ src0_component_offset);
}
Instruction *ld = mkLoad(TYPE_U32, dst0[c], sym, off);
--
2.7.3
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Re: [Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
Ah, I may have read over your commit too hastily. Will have another look.
On Apr 8, 2016 5:27 AM, "Hans de Goede" wrote:
> Hi,
>
> On 07-04-16 15:58, Ilia Mirkin wrote:
>
>> That's wrong.
>>
>
> It used to work with the old RES[] code and if one cannot specify
> a source swizzle, then how can I do something like
>
> LOAD TEMP[0].y, MEMORY[0], address
>
> And get the data at absolute global memory address "address" into
> TEMP[0].y ?
>
> This is a must-have for llvm to be able to generate working TGSI code,
> I do not see any way around this.
>
> AFAIK this is exactly what src-swizzling is for. Also note that
> this commit does not change anything if no src-swizzling is specified,
> in that case things work exactly as before.
>
> > The spec for the instruction needs to be clarified...
>
>> The current nouveau impl is correct - only the .x of the address
>> should be loaded, with up to 16 bytes read into the destination.
>>
>
> Ah note this is not about swizzling on the address, that indeed
> makes no sense given how the addressing works for BUFFERS / MEMORY,
> no this is about adding a swizlling postfix to the buffer / memory
> resource specification, for example:
>
> LOAD TEMP[0].y, MEMORY[0]., TEMP[0]
>
> See the swizzling is done on the resource, not on the address, so
> the swizzling specifies swizzling of the up to 16 bytes read from
> address, it does not influence the address handling at all.
>
> I now see I made an error in my commit msg, it gives the following
> example:
>
> LOAD TEMP[0].y, MEMORY[0]., TEMP[0].x
>
> This clearly is wrong, the last TEMP[0].x is not even valid TGSI,
> the correct example would be:
>
> LOAD TEMP[0].y, MEMORY[0]., TEMP[0]
>
> Regards,
>
> Hans
>
>
> On Thu, Apr 7, 2016 at 9:27 AM, Hans de Goede wrote:
>>
>>> The llvm TGSI backend does things like:
>>>
>>>
>>>
>>> Expecting the data at address TEMP[0].x to get loaded to
>>> TEMP[0].y. Before this commit the data at TEMP[0].x + 4 would be
>>> loaded instead. This commit fixes this.
>>>
>>> Signed-off-by: Hans de Goede
>>> ---
>>> src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp | 8 ++--
>>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
>>> b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
>>> index 557608e..cc51f5a 100644
>>> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
>>> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
>>> @@ -2279,12 +2279,16 @@ Converter::handleLOAD(Value *dst0[4])
>>>
>>>Value *off = fetchSrc(1, c);
>>>Symbol *sym;
>>> + uint32_t src0_component_offset = tgsi.getSrc(0).getSwizzle(c)
>>> * 4;
>>> +
>>>if (tgsi.getSrc(1).getFile() == TGSI_FILE_IMMEDIATE) {
>>> off = NULL;
>>> sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
>>> - tgsi.getSrc(1).getValueU32(0, info) + 4 * c);
>>> + tgsi.getSrc(1).getValueU32(0, info) +
>>> + src0_component_offset);
>>>} else {
>>> -sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c, 4 * c);
>>> +sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
>>> + src0_component_offset);
>>>}
>>>
>>>Instruction *ld = mkLoad(TYPE_U32, dst0[c], sym, off);
>>> --
>>> 2.7.3
>>>
>>>
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Re: [Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
On Fri, Apr 8, 2016 at 5:27 AM, Hans de Goede wrote: > Hi, > > On 07-04-16 15:58, Ilia Mirkin wrote: >> >> That's wrong. > > > It used to work with the old RES[] code and if one cannot specify > a source swizzle, then how can I do something like > > LOAD TEMP[0].y, MEMORY[0], address > > And get the data at absolute global memory address "address" into TEMP[0].y > ? > > This is a must-have for llvm to be able to generate working TGSI code, > I do not see any way around this. > > AFAIK this is exactly what src-swizzling is for. Also note that > this commit does not change anything if no src-swizzling is specified, > in that case things work exactly as before. > >> The spec for the instruction needs to be clarified... >> >> The current nouveau impl is correct - only the .x of the address >> should be loaded, with up to 16 bytes read into the destination. > > > Ah note this is not about swizzling on the address, that indeed > makes no sense given how the addressing works for BUFFERS / MEMORY, > no this is about adding a swizlling postfix to the buffer / memory > resource specification, for example: > > LOAD TEMP[0].y, MEMORY[0]., TEMP[0] > > See the swizzling is done on the resource, not on the address, so > the swizzling specifies swizzling of the up to 16 bytes read from > address, it does not influence the address handling at all. > > I now see I made an error in my commit msg, it gives the following > example: > > LOAD TEMP[0].y, MEMORY[0]., TEMP[0].x > > This clearly is wrong, the last TEMP[0].x is not even valid TGSI, > the correct example would be: > > LOAD TEMP[0].y, MEMORY[0]., TEMP[0] I stand by my comment of "working as intended". But that doesn't mean the intent can't be changed :) For memory/buffers, LOAD takes the address at TEMP[0].x and loads 16 bytes (4 words), and sticks them into the destination's .xyzw. If you happen to have a writemask, then only some of those are written out. It seems that you're trying to add additional meaning to the swizzle on the "memory" argument. However I don't believe that such a thing is defined. (And definitely not used anywhere, at least not on purpose.) Why does this cause you issues with LLVM-generated TGSI? -ilia ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
Hi, On 08-04-16 17:02, Ilia Mirkin wrote: On Fri, Apr 8, 2016 at 5:27 AM, Hans de Goede wrote: Hi, On 07-04-16 15:58, Ilia Mirkin wrote: That's wrong. It used to work with the old RES[] code and if one cannot specify a source swizzle, then how can I do something like LOAD TEMP[0].y, MEMORY[0], address And get the data at absolute global memory address "address" into TEMP[0].y ? This is a must-have for llvm to be able to generate working TGSI code, I do not see any way around this. AFAIK this is exactly what src-swizzling is for. Also note that this commit does not change anything if no src-swizzling is specified, in that case things work exactly as before. The spec for the instruction needs to be clarified... The current nouveau impl is correct - only the .x of the address should be loaded, with up to 16 bytes read into the destination. Ah note this is not about swizzling on the address, that indeed makes no sense given how the addressing works for BUFFERS / MEMORY, no this is about adding a swizlling postfix to the buffer / memory resource specification, for example: LOAD TEMP[0].y, MEMORY[0]., TEMP[0] See the swizzling is done on the resource, not on the address, so the swizzling specifies swizzling of the up to 16 bytes read from address, it does not influence the address handling at all. I now see I made an error in my commit msg, it gives the following example: LOAD TEMP[0].y, MEMORY[0]., TEMP[0].x This clearly is wrong, the last TEMP[0].x is not even valid TGSI, the correct example would be: LOAD TEMP[0].y, MEMORY[0]., TEMP[0] I stand by my comment of "working as intended". But that doesn't mean the intent can't be changed :) For memory/buffers, LOAD takes the address at TEMP[0].x and loads 16 bytes (4 words), and sticks them into the destination's .xyzw. If you happen to have a writemask, then only some of those are written out. It seems that you're trying to add additional meaning to the swizzle on the "memory" argument. However I don't believe that such a thing is defined. (And definitely not used anywhere, at least not on purpose.) Why does this cause you issues with LLVM-generated TGSI? When dealing with non vector variables the llvm register allocator will use TEMP[0].x then TEMP[0].y, etc. When loading something from a global buffer it will calculate the address to use, and store that in say TEMP[0].x, so it ends up generating: LOAD TEMP[0].y, MEMORY[0], TEMP[0] Expecting the contents of TEMP[0].y to become the 32 bits of data to which TEMP[0].x is pointing. But instead it will get the 32 bits of data at address (TEMP[0].x + 4). With the old RES[32767] code one could generate the following TGSI: LOAD TEMP[0].y, RES[32767]., TEMP[0] And things would work fine since the . swizzling postfix would be honored and when storing to y (the only component set in the dest-mask) the x component at address (TEMP[0].x) would be loaded, rather then the y component at (TEMP[0].y) Note that another approach would be to not increment the address by a 32 bit word for skipped (not set in destmask) components. The way I see it either: 1) We see that LOAD does not deal with vectors, but with flat memory, in which case skipping 4 bytes because x is not set in the destmask does not make sense, as that is a vector thing todo. 2) LOAD is vector layout aware in which case supporting swizzling makes sense. Currently we have a weird hybrid which is rather cumbersome to work with from a compiler pov. Regards, Hans -ilia ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
On Fri, Apr 8, 2016 at 11:28 AM, Hans de Goede wrote: > When dealing with non vector variables the llvm register allocator > will use TEMP[0].x then TEMP[0].y, etc. > > When loading something from a global buffer it will calculate the > address to use, and store that in say TEMP[0].x, so it ends up > generating: > > LOAD TEMP[0].y, MEMORY[0], TEMP[0] > > Expecting the contents of TEMP[0].y to become the 32 bits of data > to which TEMP[0].x is pointing. But instead it will get the 32 bits of > data at address (TEMP[0].x + 4). > > With the old RES[32767] code one could generate the following TGSI: > > LOAD TEMP[0].y, RES[32767]., TEMP[0] > > And things would work fine since the . swizzling postfix would > be honored and when storing to y (the only component set in the dest-mask) > the x component at address (TEMP[0].x) would be loaded, rather then the > y component at (TEMP[0].y) > > Note that another approach would be to not increment the address by > a 32 bit word for skipped (not set in destmask) components. > > The way I see it either: > > 1) We see that LOAD does not deal with vectors, but with flat memory, > in which case skipping 4 bytes because x is not set in the destmask > does not make sense, as that is a vector thing todo. > > 2) LOAD is vector layout aware in which case supporting swizzling > makes sense. > > Currently we have a weird hybrid which is rather cumbersome to > work with from a compiler pov. And I guess LLVM never ends up generating any of the other "funny" instructions like LIT and the such. Well, I have no problem adding the swizzling logic, i.e. the way that LOAD will now work (logically) is that it will (a) fetch 4 values from the coordinates provided (4 sequential dwords from src1.x in the case of buffer/memory, RGBA colors from src1.xyz in the case of images) (b) swizzle them according to the swizzle on the MEMORY/BUFFER/IMAGE argument (c) store that swizzled result into the destination based on the writemask That would sound reasonable to me, and if I understand correctly, is option 2 of your proposal. We'd need some docs updates and buy-in from the other gallium driver developers. STORE remains unchanged, as the MEMORY/etc is in the destination, where there is a writemask, which is presently used and will remain effective. -ilia ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] nouveau: codegen: Take src swizzle into account on loads
Hi, On 08-04-16 17:45, Ilia Mirkin wrote: On Fri, Apr 8, 2016 at 11:28 AM, Hans de Goede wrote: When dealing with non vector variables the llvm register allocator will use TEMP[0].x then TEMP[0].y, etc. When loading something from a global buffer it will calculate the address to use, and store that in say TEMP[0].x, so it ends up generating: LOAD TEMP[0].y, MEMORY[0], TEMP[0] Expecting the contents of TEMP[0].y to become the 32 bits of data to which TEMP[0].x is pointing. But instead it will get the 32 bits of data at address (TEMP[0].x + 4). With the old RES[32767] code one could generate the following TGSI: LOAD TEMP[0].y, RES[32767]., TEMP[0] And things would work fine since the . swizzling postfix would be honored and when storing to y (the only component set in the dest-mask) the x component at address (TEMP[0].x) would be loaded, rather then the y component at (TEMP[0].y) Note that another approach would be to not increment the address by a 32 bit word for skipped (not set in destmask) components. The way I see it either: 1) We see that LOAD does not deal with vectors, but with flat memory, in which case skipping 4 bytes because x is not set in the destmask does not make sense, as that is a vector thing todo. 2) LOAD is vector layout aware in which case supporting swizzling makes sense. Currently we have a weird hybrid which is rather cumbersome to work with from a compiler pov. And I guess LLVM never ends up generating any of the other "funny" instructions like LIT and the such. Well, I have no problem adding the swizzling logic, i.e. the way that LOAD will now work (logically) is that it will (a) fetch 4 values from the coordinates provided (4 sequential dwords from src1.x in the case of buffer/memory, RGBA colors from src1.xyz in the case of images) (b) swizzle them according to the swizzle on the MEMORY/BUFFER/IMAGE argument (c) store that swizzled result into the destination based on the writemask That would sound reasonable to me, and if I understand correctly, is option 2 of your proposal. Yes that is option 2, and is basically what the patch which started this thread does. So that would work for me :) We'd need some docs updates and buy-in from the other gallium driver developers. What docs would need updating ? The TGSI docs I'm aware of are at: http://gallium.readthedocs.org/en/latest/tgsi.html I assume those have a source in the mesa src somewhere (I've not looked), but those mostly just look quite incomplete in general when it comes to TGSI (I've had to revert to figuring what things do from the mesa srcs quite often) Have I been looking at the wrong docs perhaps ? Note that them being incomplete is not intended as an excuse to not document this, I'm all for better documentation. STORE remains unchanged, as the MEMORY/etc is in the destination, where there is a writemask, which is presently used and will remain effective. Right and note that the first src operand of STORE already takes swizzling into account, so the proposed option 2 will actually make the 2 more inline. Regards, Hans ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
