[LLVMdev] (no subject)

[Duncan Sands]

Hi Umesh,

> Again ,I'm newbie to LLVM  and please pardon me ..if you guys  feel that ,the
> below question is very basic :)
>
> Here i go ,compiled the below sample with clang i.e *clang enum.c -S -emit-llvm*
> and there respective file are
>
> $ cat enum.c
> int main()
> {
>   enum type{one=1,two,three} s;
>   s = one;
>   return s;
> }
>
> $ cat enum.s
> ; ModuleID = 'enum.c'
> target datalayout =
> "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S32"
> target triple = "i386-pc-cygwin"
>
> define i32 @main() nounwind {
>    %1 = alloca i32, align 4
>    %s = alloca i32, align 4
>    store i32 0, i32* %1
>    store i32 1, i32* %s, align 4
>    %2 = load i32* %s, align 4
>    ret i32 %2
> }
>
> *Question :* Why there is  extra 4 bytes on stack i.e *"%1 = alloca i32, align
> 4"*  ???

I think this would normally be used for storing the return value in more
complicated cases.  If you compile with optimization it will go away.

Ciao, Duncan.