[PATCH vkd3d 4/6] vkd3d-shader/hlsl: Write SM4 greater-than instructions.

[Zebediah Figura (she/her)]

On 12/17/21 14:40, Giovanni Mascellani wrote:
> Hi,
> 
> On 17/12/21 19:07, Zebediah Figura (she/her) wrote:
>> Should we lower these at parse time instead?
>>
>> Same for LE -> GE.
> 
> Don't know. I have to say that I was genuinely surprised that we allowed 
> so much redundancy in the IR, but certainly it won't be me the one who 
> complains about having an expressive IR. So, given that it had already 
> been accepted, I didn't protest.

Well, that code is old, and a lot of the old code doesn't really reflect 
current preferred design principles.

> My feeling is that when your compiler isn't able to handle most trivial 
> arithmetic operators it is a bit early to enter fine discussions about 
> how to best trim the IR so that optimization phases that do not exist 
> yet might be a little bit better or not.
I don't think it's really about optimization in this case. Rather, if we 
just do something as simple as

-            $$ = add_binary_comparison_expr_merge(ctx, $1, $3, 
HLSL_OP2_GREATER, @2);
+            $$ = add_binary_comparison_expr_merge(ctx, $3, $1, 
HLSL_OP2_LESS, @2);


then this patch suddenly doesn't become necessary anymore.