Mesa (main): aco/ra: omit VCC affinity on VOPC_SDWA for GFX9+

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Module: Mesa
Branch: main
Commit: 415a3820fc1899fed11d5743514821f0adb3eec1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=415a3820fc1899fed11d5743514821f0adb3eec1

Author: Daniel Schürmann <daniel at schuermann.dev>
Date:   Tue Mar 15 13:06:48 2022 +0100

aco/ra: omit VCC affinity on VOPC_SDWA for GFX9+

VOPC_SDWA can also use arbitrary SGPR pairs on GFX9+.

Totals from 5607 (4.16% of 134913) affected shaders: (GFX10.3)
CodeSize: 42470760 -> 42452988 (-0.04%)
Instrs: 7943174 -> 7942883 (-0.00%)
Latency: 102887029 -> 102886305 (-0.00%); split: -0.00%, +0.00%
InvThroughput: 20454456 -> 20454338 (-0.00%); split: -0.00%, +0.00%
Copies: 376818 -> 376865 (+0.01%); split: -0.00%, +0.01%

Reviewed-by: Rhys Perry <pendingchaos02 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15408>

---

 src/amd/compiler/aco_register_allocation.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/amd/compiler/aco_register_allocation.cpp b/src/amd/compiler/aco_register_allocation.cpp
index 314955061ff..9560aed7742 100644
--- a/src/amd/compiler/aco_register_allocation.cpp
+++ b/src/amd/compiler/aco_register_allocation.cpp
@@ -2394,7 +2394,8 @@ get_affinities(ra_ctx& ctx, std::vector<IDSet>& live_out_per_block)
                     instr->operands[0].isFirstKillBeforeDef()) {
             ctx.split_vectors[instr->operands[0].tempId()] = instr.get();
          } else if (instr->isVOPC() && !instr->isVOP3()) {
-            ctx.assignments[instr->definitions[0].tempId()].vcc = true;
+            if (!instr->isSDWA() || ctx.program->chip_class == GFX8)
+               ctx.assignments[instr->definitions[0].tempId()].vcc = true;
          } else if (instr->isVOP2() && !instr->isVOP3()) {
             if (instr->operands.size() == 3 && instr->operands[2].isTemp() &&
                 instr->operands[2].regClass().type() == RegType::sgpr)