[clang] [llvm] [HLSL] Adding Flatten and Branch if attributes (PR #116331)

[Chris B via cfe-commits]

================
@@ -2776,19 +2788,23 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
     }
     return MIB.constrainAllUses(TII, TRI, RBI);
   }
-  case Intrinsic::spv_loop_merge:
-  case Intrinsic::spv_selection_merge: {
-    const auto Opcode = IID == Intrinsic::spv_selection_merge
-                            ? SPIRV::OpSelectionMerge
-                            : SPIRV::OpLoopMerge;
-    auto MIB = BuildMI(BB, I, I.getDebugLoc(), TII.get(Opcode));
+  case Intrinsic::spv_loop_merge: {
+    auto MIB = BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpLoopMerge));
     for (unsigned i = 1; i < I.getNumExplicitOperands(); ++i) {
       assert(I.getOperand(i).isMBB());
       MIB.addMBB(I.getOperand(i).getMBB());
     }
     MIB.addImm(SPIRV::SelectionControl::None);
     return MIB.constrainAllUses(TII, TRI, RBI);
   }
+  case Intrinsic::spv_selection_merge: {
+    auto MIB =
+        BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpSelectionMerge));
+    assert(I.getOperand(1).isMBB());
----------------
llvm-beanz wrote:

nit: strings added to asserts make it a lot easier to understand and find problems.
```suggestion
    assert(I.getOperand(1).isMBB() &&
           "operand 1 to spv_selection_merge must be a basic block");
```

https://github.com/llvm/llvm-project/pull/116331