Codegen regression on master

[jiahao]

Sorry for the vague title, but I'm not sure what the problem is.

Here is a MWE:

immutable Clock
    hour::Int
    on_minute#::Bool #<-- Uncomment this annotation to cause codegen failure
end
Clock(hour::Integer) = Clock(Int(hour), false)

Base.zero(::Type{Clock}) = Clock(12, false)

A = zeros(Clock, 3, 3)
eigs(A)

With the second field un-annotated, eigs throws an expected error:

WARNING: Adjusting nev from 6 to 1
ERROR: LoadError: MethodError: `convert` has no method matching convert(::Type{Clock}, ::Float64)
This may have arisen from a call to the constructor Clock(...),
since type constructors fall back to convert methods.
...

With the annotation, codegen.cpp vomits on master:

signal (11): Segmentation fault: 11
_ZN4llvm11PointerType3getEPNS_4TypeEj at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
_ZN4llvm15SimplifyGEPInstENS_8ArrayRefIPNS_5ValueEEERKNS_10DataLayoutEPKNS_17TargetLibraryInfoEPKNS_13DominatorTreeEPNS_15AssumptionCacheEPKNS_11InstructionE at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
_ZN4llvm12InstCombiner22visitGetElementPtrInstERNS_17GetElementPtrInstE at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
_ZN4llvm12InstCombiner3runEv at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
_ZL31combineInstructionsOverFunctionRN4llvm8FunctionERNS_19InstCombineWorklistEPNS_13AliasAnalysisERNS_15AssumptionCacheERNS_17TargetLibraryInfoERNS_13DominatorTreeEPNS_8LoopInfoE at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
_ZN12_GLOBAL__N_124InstructionCombiningPass13runOnFunctionERN4llvm8FunctionE at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
_ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
_ZN4llvm6legacy23FunctionPassManagerImpl3runERNS_8FunctionE at /Users/jiahao/local/src/julia/usr/lib/libjulia-debug.dylib (unknown line)
to_function at /Users/jiahao/local/src/julia/src/codegen.cpp:839
jl_compile at /Users/jiahao/local/src/julia/src/codegen.cpp:973
jl_get_specialization at /Users/jiahao/local/src/julia/src/gf.c:1475
...

0.4 correctly throws the "no convert method" error in both cases.

(Discovered by @malmaud in CoolClocks.jl)

[malmaud]

⏳

[simonster]

Minimal reproducer (sorry, no clocks):

julia> immutable X
              a::Int
              b::Bool
       end

julia> function f(x)
           z = false
           z = x
           x === z
       end;

julia> f(X(1, false))
Assertion failed: (Ty && "Invalid GetElementPtrInst indices for type!"), function checkGEPType, file /usr/local/julia/usr/include/llvm/IR/Instructions.h, line 704.

signal (6): Abort trap: 6
__pthread_kill at /usr/lib/system/libsystem_kernel.dylib (unknown line)
fish: Job 1, 'julia' terminated by signal SIGABRT (Abort)

z is boxed and the codegen appears to be trying to do a GEP on the jl_value_t*.