[LLVMdev] llvm-as and implicit value naming

[Chris Lattner]

On Sep 25, 2008, at 7:10 AM, Mark Shannon wrote:

> Hi everyone,
>
> I don't know if this is a bug or I am misunderstanding things.
> I couldn't find anything in the Bugzilla database.
>
> The following code:
>
> 1 @sp = external global i8**		; <i8***>
> 2
> 3 define void @test(i8* %x) {
> 4 entry:
> 5	load i8*** @sp	; <i8**>:1
> 6	getelementptr i8** %1, i32 1 ; <i8**>:2
> 7	store i8** %2, i8*** @sp, align 4
> 8	ret void
> 9 }
>
> causes llvm-as (version 2.3) to choke:
> llvm-as: test.ll:7,0: Reference to an invalid definition: #2 of type  
> 'i8 * *'

First, note that the comments ("; ...") are completely ignored.  I  
assume that there was another line, that you deleted.  Because of  
that, line #5 actually defines %0 (not %1).  Because of that, line 6  
defines %1, and there is no %2.


> There are variations, such as:
>
> 1 @sp = external global i8**		; <i8***>
> 2
> 3 define void @test(i32 %X) {
> 4 entry:
> 5	load i8*** @sp	; <i8**>:1
> 6	getelementptr i8** %1, i32 -1		; <i8**> :2
> 7	store i8** %2, i8*** @sp, align 4
> 8	inttoptr i32 %X to i8*		; <i8*> :3
> 9	store i8* %3, i8** %2, align 4
> 10 	ret void
> 11}
>
> which produces
> llvm-as: test.ll:9,0: Numbered value (%2) of type 'i8 *' does not  
> match expected type, 'i8 * *'

This is the same sort of thing, because you're off by one, you're  
referring to the wrong value.

-Chris