RDNA assembly backend ($1000 bounty) (#787)

* Revert "Revert "ops rdna""

This reverts commit 0400315078.

* Revert "Revert "writing 2""

This reverts commit 325a3bf2cf.

* no dump

* 2x 2

* simple asm

* local size

* sub

* lil work

* support args != 3

* assembler work

* generate that

* ptx assembler

* begin index renderer

* max

* ptx loops

* gemms work

* valid works

* asm working a bit more

* close

* passing all ops tests

* ptx is a codegen only, not a backend

* ptx

* float16 support

* rdna goes here

* install types

* make amd disassemble

* ansilen for pretty print

* fix ptx log2/exp2

* assemblyinstruction

* new asm

* working gemm

* fix cmp

* more passing

* mod

* ptx works again

* rdan3 add works

* log exp

* sin is sin 2pi

* fix types

* progress

* loops work

* rdna xyz

* better addressing

* cleanups

* handle exception in early process

* div support

* rdna float4

* locals work

* fix neg index

* cast

* smaller diff

* yaml

* import only if selected

* fromimport

* types

* this all needs rewriting

* a few more

tinygrad/codegen/cstyle.py

@@ -172,8 +172,8 @@ def uops_to_cstyle(uops:List[UOp], bufs:List[Union[LocalBuffer,LazyBuffer]], lan
     [', '.join([f'{t} {bufnames[i]}' for i,t in buftypes] + lang.extra_args)] +
     [") {\n"] + list(prekernel) + ['\n'.join(kernel), "\n}"])
 
-  if lang.half_prekernel: prg =''.join([f"{lang.half_prekernel}", "\n", prg])
-  if lang.double_prekernel: prg = ''.join([f"{lang.double_prekernel}", "\n", prg])
+  if lang.half_prekernel and any(x.dtype == dtypes.float16 for x in bufs): prg = ''.join([f"{lang.half_prekernel}", "\n", prg])
+  if lang.double_prekernel and any(x.dtype == dtypes.float64 for x in bufs): prg = ''.join([f"{lang.double_prekernel}", "\n", prg])
   return prg, global_size, local_size
 
 class CStyleCodegen(Linearizer):