ac/nir_to_llvm: add assert to emit_bcsel()

nir to llvm assumes we have already split vectors to scalars via
nir_lower_alu_to_scalar().

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/amd/common/ac_nir_to_llvm.c

@@ -268,6 +268,8 @@ static LLVMValueRef emit_intrin_3f_param(struct ac_llvm_context *ctx,
 static LLVMValueRef emit_bcsel(struct ac_llvm_context *ctx,
 			       LLVMValueRef src0, LLVMValueRef src1, LLVMValueRef src2)
 {
+	assert(LLVMGetTypeKind(LLVMTypeOf(src0)) != LLVMVectorTypeKind);
+
 	LLVMValueRef v = LLVMBuildICmp(ctx->builder, LLVMIntNE, src0,
 				       ctx->i32_0, "");
 	return LLVMBuildSelect(ctx->builder, v,