engine/rr: cheaper bounds checks and conversion guards in the translated passes

- ptx2rr.py fetch0 (the translation's bounds-checked texel fetch): one
  unsigned comparison per axis instead of two signed ones; a negative
  coordinate is above every size. enc0's gather fetches 102 times: 231
  instructions fewer, scalar spills 200 -> 176.
- The output passes (post, down, downp, pooled) also go through
  spv_exact_convert.py now and take ptx2rr.py --exact-convert's single f32
  guard on binary16 conversions, as the hybrid stages do. Their ISA already
  uses v_fma_mix*_f16 for plain conversions, so the check is the whole
  instruction mix: only v_and_or_b32 / v_or / v_perm / shifts go (post -16
  VALU, down -9, downp -73); every v_fma_f32 / v_mul_f32 / v_add_f32 /
  conversion / v_exp / v_log count is unchanged.

Every image byte-identical on the replay inputs (also robustness2 and the
split gather build). RX 9070 XT, 720p -> 1440p: enc0 745 -> 738 us, output
673 -> 665 us.

Signed-off-by: itchyfeetleech <[email protected]>

engine/compile_rr2.py

@@ -168,8 +168,9 @@ def main():
         cmd += [f'--buffer={off}' for off in BUFFERS.get(stage, [])]
         cmd += [f'--snorm16={off}' for off in SNORM16.get(stage, [])]
         cmd += [f'--surface={off}={fmt}' for off, fmt in SURFACES.get(stage, {}).items()]
-        # the hybrid stages' modules go through spv_exact_convert.py, so their conversions need only the lighter guard
-        exact = bool(a.native) and stage in HYBRID
+        # the hybrid stages' and the output passes' modules go through spv_exact_convert.py, so their conversions need
+        # only the lighter guard (ptx2rr.py --exact-convert)
+        exact = (bool(a.native) and stage in HYBRID) or not network
         cmd += ['--exact-convert'] if exact else []
         subprocess.run(cmd, check=True, stderr=subprocess.DEVNULL)
         info = json.loads(generated.with_suffix('.json').read_text())
@@ -210,6 +211,9 @@ def main():
         else:
             subprocess.run(capped + ['glslangValidator', '-V', '--target-env', 'vulkan1.3', str(generated), '-o',
                                      str(out / f'{stage}.spv')], check=True, stdout=subprocess.DEVNULL)
+            if exact:
+                subprocess.run([sys.executable, str(HERE / 'rr' / 'spv_exact_convert.py'), str(out / f'{stage}.spv')],
+                               check=True, stdout=subprocess.DEVNULL)
         if hybrid:
             pass
         elif network: