AMDGPU: Minor SDWA pass cleanups

[arsenm]

Don't use low level regclass query in SDWA pass.

[arsenm]

• AMDGPU: Minor SDWA pass cleanups #166629 👈 (View in Graphite)
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[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: Matt Arsenault (arsenm)

Changes

Don't use low level regclass query in SDWA pass.

---

Full diff: https://github.com/llvm/llvm-project/pull/166629.diff

1 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp (+11-10)

diff --git a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
index bfac639b6de09..caff354c73510 100644
--- a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
+++ b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
@@ -1334,20 +1334,21 @@ void SIPeepholeSDWA::legalizeScalarOperands(MachineInstr &MI,
   const MCInstrDesc &Desc = TII->get(MI.getOpcode());
   unsigned ConstantBusCount = 0;
   for (MachineOperand &Op : MI.explicit_uses()) {
-    if (!Op.isImm() && !(Op.isReg() && !TRI->isVGPR(*MRI, Op.getReg())))
-      continue;
-
-    unsigned I = Op.getOperandNo();
+    if (Op.isReg()) {
+      if (TRI->isVGPR(*MRI, Op.getReg()))
+        continue;
 
-    int16_t RegClass = TII->getOpRegClassID(Desc.operands()[I]);
-    if (RegClass == -1 || !TRI->isVSSuperClass(TRI->getRegClass(RegClass)))
+      if (ST.hasSDWAScalar() && ConstantBusCount == 0) {
+        ++ConstantBusCount;
+        continue;
+      }
+    } else if (!Op.isImm())
       continue;
 
-    if (ST.hasSDWAScalar() && ConstantBusCount == 0 && Op.isReg() &&
-        TRI->isSGPRReg(*MRI, Op.getReg())) {
-      ++ConstantBusCount;
+    unsigned I = Op.getOperandNo();
+    const TargetRegisterClass *OpRC = TII->getRegClass(Desc, I, TRI);
+    if (!OpRC || !TRI->isVSSuperClass(OpRC))
       continue;
-    }
 
     Register VGPR = MRI->createVirtualRegister(&AMDGPU::VGPR_32RegClass);
     auto Copy = BuildMI(*MI.getParent(), MI.getIterator(), MI.getDebugLoc(),