spirv-opt crashes when optimizing function declarations

[cheneym2]

When spv input to spirv-opt contains functions without blocks (declarations), some optimization passes crash. It seems that they assume functions will have blocks.

 %normalFunc = OpFunction %int None %26
          %a = OpFunctionParameter %int
               OpFunctionEnd

; SPIR-V
; Version: 1.5
; Generator: Khronos; 40
; Bound: 36
; Schema: 0
               OpCapability Linkage
               OpCapability RayTracingKHR
               OpCapability Shader
               OpExtension "SPV_KHR_ray_tracing"
               OpMemoryModel Logical GLSL450
               OpEntryPoint AnyHitKHR %anyhit "main" %Constants %8
               OpSource Slang 1
               OpName %Payload "Payload"
               OpMemberName %Payload 0 "val"
               OpName %SLANG_ParameterGroup_Constants_std140 "SLANG_ParameterGroup_Constants_std140"
               OpMemberName %SLANG_ParameterGroup_Constants_std140 0 "x"
               OpMemberName %SLANG_ParameterGroup_Constants_std140 1 "y"
               OpName %Constants "Constants"
               OpName %a "a"
               OpName %normalFunc "normalFunc"
               OpName %a_0 "a"
               OpName %normalFuncUsesGeneric "normalFuncUsesGeneric"
               OpName %anyhit "anyhit"
               OpMemberDecorate %Payload 0 Offset 0
               OpDecorate %SLANG_ParameterGroup_Constants_std140 Block
               OpMemberDecorate %SLANG_ParameterGroup_Constants_std140 0 Offset 0
               OpMemberDecorate %SLANG_ParameterGroup_Constants_std140 1 Offset 4
               OpDecorate %Constants Binding 0
               OpDecorate %Constants DescriptorSet 0
               OpDecorate %normalFunc LinkageAttributes "_SR29export_2Dxlibrary_2Dxgenerics10normalFuncp1pi_ii" Import
               OpDecorate %normalFuncUsesGeneric LinkageAttributes "_SR29export_2Dxlibrary_2Dxgenerics21normalFuncUsesGenericp1pi_ii" Import
       %void = OpTypeVoid
          %3 = OpTypeFunction %void
        %int = OpTypeInt 32 1
    %Payload = OpTypeStruct %int
%_ptr_IncomingRayPayloadKHR_Payload = OpTypePointer IncomingRayPayloadKHR %Payload
      %int_0 = OpConstant %int 0
%_ptr_IncomingRayPayloadKHR_int = OpTypePointer IncomingRayPayloadKHR %int
      %float = OpTypeFloat 32
%SLANG_ParameterGroup_Constants_std140 = OpTypeStruct %float %float
%_ptr_Uniform_SLANG_ParameterGroup_Constants_std140 = OpTypePointer Uniform %SLANG_ParameterGroup_Constants_std140
%_ptr_Uniform_float = OpTypePointer Uniform %float
      %int_1 = OpConstant %int 1
         %26 = OpTypeFunction %int %int
          %8 = OpVariable %_ptr_IncomingRayPayloadKHR_Payload IncomingRayPayloadKHR
  %Constants = OpVariable %_ptr_Uniform_SLANG_ParameterGroup_Constants_std140 Uniform
 %normalFunc = OpFunction %int None %26
          %a = OpFunctionParameter %int
               OpFunctionEnd
%normalFuncUsesGeneric = OpFunction %int None %26
        %a_0 = OpFunctionParameter %int
               OpFunctionEnd
     %anyhit = OpFunction %void None %3
          %4 = OpLabel
         %11 = OpAccessChain %_ptr_IncomingRayPayloadKHR_int %8 %int_0
         %17 = OpAccessChain %_ptr_Uniform_float %Constants %int_0
         %18 = OpLoad %float %17
         %20 = OpAccessChain %_ptr_Uniform_float %Constants %int_1
         %21 = OpLoad %float %20
         %22 = OpFMul %float %18 %21
         %23 = OpConvertFToS %int %22
         %24 = OpFunctionCall %int %normalFunc %23
         %28 = OpLoad %float %20
         %29 = OpConvertFToS %int %28
         %30 = OpFunctionCall %int %normalFuncUsesGeneric %29
         %33 = OpIAdd %int %24 %30
               OpStore %11 %33
               OpReturn
               OpFunctionEnd