[LLVMdev] LLVM-GCC & GV zeroinitializers, 2.5 vs 2.6.

[Ray Fix]

On Sep 10, 2009, at 11:10 PM, Samuel Crow wrote:
> I think the reason for the change was because there is processor  
> context information stored in the type in 2.6.  The reason it's  
> there is to support multicore JIT architecture.

Interesting.  FWIW, clang-cc -emit-llvm also produces something  
similar but not quite the same:

>> From: Julien Lerouge <jlerouge at apple.com>
>> I have a small piece of C code written like this:
>>
>>    typedef struct {
>>        char a;
>>        int b;
>>        int c;
>>    } foo;
>>
>>    foo myFoo[5] = {{0}};


%0 = type <{ %1, %struct.anon, %struct.anon, %struct.anon,  
%struct.anon }>
%1 = type { i8, [11 x i8] }
%struct.anon = type { i8, i32, i32 }

@myFoo = global %0 zeroinitializer, align 4       ; <%0*> [#uses=0]

So that [11 x i8] is somehow for multicore JIT?  It produces this even  
if the architecture is set to blackfin.   This seems pretty weird and  
non-intuitive to me too.  I would be interested in learning about the  
rationale. Ultimately clang is storing 3 bytes extra in the lead  
element, llvm-gcc has 3*5=15.

Ray