[LLVMdev] LLVM GCC and Malloc

Chris Lattner sabre at nondot.org
Tue May 22 22:19:09 PDT 2007

On Tue, 22 May 2007, Ben Chambers wrote:
> I've noticed a slight difference between the code emitted by LLVM-GCC
> and what the online demo emits.  For instance, the C code:

The primary reason for this is that the demo page is running LLVM 1.9, 
where mainline more closely resembles LLVM 2.0.  When 2.0 is done (real 
soon now) we'll switch it over.

>   malloc (5 * sizeof(int))
> becomes
>   malloc [5 x int]
> when using the online demo, and
>   call @malloc (i32 20)
> when using llvm-gcc.
> I understand that the effective behavior is the same thing, but for
> some work that I'm doing it's much better to have the malloc [5 x
> int], because it is more detailed.  Is there some way to get llvm-gcc
> to emit this information, or an optimization pass I can run to recover
> this more detailed information?

Are you passing -O3 to llvm-gcc?  This could be a case where the 
raiseallocs pass is missing turning the malloc call into a malloc 
instruction.  If -O3 doesn't help, please file a bugzilla and we can fix 
it.  Thanks!



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