[AMDGPU] Make getInstSizeInBytes more generic

NFC. This check mainly handles size affecting literals. Make it check all
explicit operands instead of a few by name. Also make the isLiteral
check handle the KIMM operands, see https://reviews.llvm.org/D111067

Change-Id: I1a362d55b2a10f5c74d445272e8b7829a8b77597

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D113318

Change-Id: Ie6c688f30a71e0335d1c6dd1ff65019bd7ce684e

Author: Sisyph

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

@@ -3471,6 +3471,9 @@ bool SIInstrInfo::isInlineConstant(const MachineOperand &MO,
     uint32_t Trunc = static_cast<uint32_t>(Imm);
     return AMDGPU::isInlinableLiteralV216(Trunc, ST.hasInv2PiInlineImm());
   }
+  case AMDGPU::OPERAND_KIMM32:
+  case AMDGPU::OPERAND_KIMM16:
+    return false;
   default:
     llvm_unreachable("invalid bitwidth");
   }
@@ -7307,31 +7310,19 @@ unsigned SIInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
     return Size;
   }
 
-  // 4-byte instructions may have a 32-bit literal encoded after them. Check
-  // operands that coud ever be literals.
+  // Instructions may have a 32-bit literal encoded after them. Check
+  // operands that could ever be literals.
   if (isVALU(MI) || isSALU(MI)) {
-    int Src0Idx = AMDGPU::getNamedOperandIdx(Opc, AMDGPU::OpName::src0);
-    if (Src0Idx == -1)
-      return DescSize; // No operands.
-
-    if (isLiteralConstantLike(MI.getOperand(Src0Idx), Desc.OpInfo[Src0Idx]))
-      return isVOP3(MI) ? 12 : (DescSize + 4);
-
-    int Src1Idx = AMDGPU::getNamedOperandIdx(Opc, AMDGPU::OpName::src1);
-    if (Src1Idx == -1)
-      return DescSize;
-
-    if (isLiteralConstantLike(MI.getOperand(Src1Idx), Desc.OpInfo[Src1Idx]))
-      return isVOP3(MI) ? 12 : (DescSize + 4);
-
-    int Src2Idx = AMDGPU::getNamedOperandIdx(Opc, AMDGPU::OpName::src2);
-    if (Src2Idx == -1)
+    if (isDPP(MI))
       return DescSize;
-
-    if (isLiteralConstantLike(MI.getOperand(Src2Idx), Desc.OpInfo[Src2Idx]))
-      return isVOP3(MI) ? 12 : (DescSize + 4);
-
-    return DescSize;
+    bool HasLiteral = false;
+    for (int I = 0, E = MI.getNumExplicitOperands(); I != E; ++I) {
+      if (isLiteralConstant(MI, I)) {
+        HasLiteral = true;
+        break;
+      }
+    }
+    return HasLiteral ? DescSize + 4 : DescSize;
   }
 
   // Check whether we have extra NSA words.