Given 2 GEPs as follows,
%tmp124 = getelementptr inbounds %struct.termbox* %termptr.1, i32 0, i32 5, !dbg !1051 ; <[2 x i16]> [#uses=1]
%tmp125 = getelementptr inbounds [2 x i16] %tmp124, i64 0, i64 0, !dbg !1051 ; <i16*> [#uses=1]
can I replace the 2nd one with
%tmp126 = getelementptr inbounds %struct.termbox* %termptr.1, i32 0, i32 5, i64 0, i64 0 ; <i16*>
When I try to create this instruction i get the follwoing error,
opt: /home/vadve/aggarwa4/llvm27/llvm-2.7/include/llvm/Instructions.h:276: const llvm::Type* llvm::checkType(const llvm::Type*): Assertion `Ty && “Invalid GetElementPtrInst indices for type!”’ failed.
Thanks!
Arushi
Given 2 GEPs as follows,
%tmp124 = getelementptr inbounds %struct.termbox* %termptr.1, i32 0, i32 5, !dbg !1051 ; <[2 x i16]*> [#uses=1]
%tmp125 = getelementptr inbounds [2 x i16]* %tmp124, i64 0, i64 0, !dbg !1051 ; <i16*> [#uses=1]
can I replace the 2nd one with
%tmp126 = getelementptr inbounds %struct.termbox* %termptr.1, i32 0, i32 5, i64 0, i64 0 ; <i16*>
You should double-check the LangRef manual, but I think the problem stems from the fact that a GEP returns a pointer to the type found after all indexing is completed.
So, in %tmp124, indexing %termptr.1 by i32 0 and i32 5 yields a [2xi16] type, and then the result of the GEP is a pointer to that, which is of type [2xi16] *.
In the new GEP you've created, I think you can remove the first i64 0 index because the result of indexing i32 0 and i32 5 is a [2 x i16] and not a [2 x i16] *.
-- John T.
Thanks John. You are right.
Is this also true for constant GEP expressions? Do they also create a pointer to the calculated type? The language manual does not state so explicitly.
Arushi