diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -4294,13 +4294,22 @@
       continue;
     }
 
-    if (RI.hasAGPRs(MRI.getRegClass(MO.getReg())) &&
-        !isOperandLegal(MI, Idx, &MO)) {
+    bool IsSGPR = false;
+    bool IsAGPR = false;
+    if (MO.getReg().isVirtual()) {
+      IsAGPR = RI.hasAGPRs(MRI.getRegClass(MO.getReg()));
+      IsSGPR = RI.isSGPRClass(MRI.getRegClass(MO.getReg()));
+    } else {
+      IsAGPR = RI.isAGPR(MRI, MO.getReg());
+      IsAGPR = RI.isSGPRReg(MRI, MO.getReg());
+    }
+
+    if (IsAGPR && !isOperandLegal(MI, Idx, &MO)) {
       legalizeOpWithMove(MI, Idx);
       continue;
     }
 
-    if (!RI.isSGPRClass(MRI.getRegClass(MO.getReg())))
+    if (!IsSGPR)
       continue; // VGPRs are legal
 
     // We can use one SGPR in each VOP3 instruction prior to GFX10
@@ -5929,9 +5938,14 @@
 
     // If this could be a VGPR or an SGPR, Check the dynamic register class.
     Register Reg = MO.getReg();
-    const TargetRegisterClass *RegRC = MRI.getRegClass(Reg);
-    if (RI.isSGPRClass(RegRC))
-      UsedSGPRs[i] = Reg;
+    if (Reg.isVirtual()) {
+      const TargetRegisterClass *RegRC = MRI.getRegClass(Reg);
+      if (RI.isSGPRClass(RegRC))
+        UsedSGPRs[i] = Reg;
+    } else {
+      if (RI.isSGPRReg(MRI, Reg))
+        UsedSGPRs[i] = Reg;
+    }
   }
 
   // We don't have a required SGPR operand, so we have a bit more freedom in
diff --git a/llvm/test/CodeGen/AMDGPU/vop3-physical-reg.mir b/llvm/test/CodeGen/AMDGPU/vop3-physical-reg.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/vop3-physical-reg.mir
@@ -0,0 +1,42 @@
+# RUN: llc -march=amdgcn -mcpu=kaveri -run-pass=si-peephole-sdwa -o - %s | FileCheck -check-prefix=CI -check-prefix=GCN %s
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=si-peephole-sdwa -o - %s | FileCheck -check-prefix=VI -check-prefix=GCN %s
+# RUN: llc -march=amdgcn -mcpu=gfx900 -run-pass=si-peephole-sdwa -o - %s | FileCheck -check-prefix=GFX9 -check-prefix=GCN %s
+# RUN: llc -march=amdgcn -mcpu=gfx1010 -run-pass=si-peephole-sdwa -o - %s | FileCheck -check-prefix=GFX10 -check-prefix=GCN %s
+
+# Allow physical registers as vop3 operands
+
+# GCN-LABEL: {{^}}name: vop3_reg
+
+# GCN: %{{[0-9]+}}:vgpr_32 = V_BCNT_U32_B32_e64 $exec_lo, 0, implicit-def $vcc, implicit $exec
+# GCN: %{{[0-9]+}}:vgpr_32 = V_BCNT_U32_B32_e64 $exec_hi, 0, implicit-def $vcc, implicit $exec
+# GCN: %{{[0-9]+}}:vgpr_32 = V_MBCNT_LO_U32_B32_e64 $exec_lo, 0, implicit-def $vcc, implicit $exec
+# GCN: %{{[0-9]+}}:vgpr_32 = V_MBCNT_HI_U32_B32_e64 $exec_hi, %{{[0-9]+}}, implicit-def $vcc, implicit $exec
+
+---
+name:            vop3_reg
+tracksRegLiveness: true
+registers:
+  - { id: 0, class: vreg_64 }
+  - { id: 1, class: vgpr_32 }
+  - { id: 2, class: vgpr_32 }
+  - { id: 3, class: vgpr_32 }
+  - { id: 4, class: vgpr_32 }
+  - { id: 9, class: sreg_64 }
+body:             |
+  bb.0:
+    liveins: $vgpr0_vgpr1, $vgpr2, $sgpr30_sgpr31
+
+    %9 = COPY $sgpr30_sgpr31
+    %0 = COPY $vgpr0_vgpr1
+
+    %1 = V_BCNT_U32_B32_e64 $exec_lo, 0, implicit-def $vcc, implicit $exec
+    %2 = V_BCNT_U32_B32_e64 $exec_hi, 0, implicit-def $vcc, implicit $exec
+    %3 = V_MBCNT_LO_U32_B32_e64 $exec_lo, 0, implicit-def $vcc, implicit $exec
+    %4 = V_MBCNT_HI_U32_B32_e64 $exec_hi, %3, implicit-def $vcc, implicit $exec
+
+    FLAT_STORE_DWORD %0, %1, 0, 0, 0, 0, implicit $exec, implicit $flat_scr :: (store 4)
+    FLAT_STORE_DWORD %0, %2, 0, 0, 0, 0, implicit $exec, implicit $flat_scr :: (store 4)
+    FLAT_STORE_DWORD %0, %3, 0, 0, 0, 0, implicit $exec, implicit $flat_scr :: (store 4)
+    FLAT_STORE_DWORD %0, %4, 0, 0, 0, 0, implicit $exec, implicit $flat_scr :: (store 4)
+    $sgpr30_sgpr31 = COPY %9
+    S_SETPC_B64_return $sgpr30_sgpr31