[PATCH v2] llvm: fix output OP_ADD mixed with pointers

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

In sparse, pointer arithmetic and accessing the field
of a structure or an array is simply done via OP_ADD,
the offset being calculated at evaluation time.
On the other hand, LLVM allows addition only on two
integers and pointer arithmetic/member access must be
done either via 'getelementptr' or the pointer must be
casted to and fro an integer.

sparse-llvm didn't took this in account which resulted
in type error in 'add' instructions.

Fix this by catching addition involving pointer and
the already existing helper calc_gep() for these.

Originally-by: Dibyendu Majumdar <mobile@majumdar.org.uk>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---

Changes since v1:
- use calc_gep() to issue the 'getelementptr' in order to use the
  offset value.

 sparse-llvm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sparse-llvm.c b/sparse-llvm.c
index 27cc1b88c..bd57730d4 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -472,6 +472,10 @@ static void output_op_binary(struct function *fn, struct instruction *insn)
 	case OP_ADD:
 		if (symbol_is_fp_type(insn->type))
 			target = LLVMBuildFAdd(fn->builder, lhs, rhs, target_name);
+		else if (LLVMGetTypeKind(LLVMTypeOf(lhs)) == LLVMPointerTypeKind)
+			target = calc_gep(fn->builder, lhs, rhs);
+		else if (LLVMGetTypeKind(LLVMTypeOf(rhs)) == LLVMPointerTypeKind)
+			target = calc_gep(fn->builder, rhs, lhs);
 		else
 			target = LLVMBuildAdd(fn->builder, lhs, rhs, target_name);
 		break;
-- 
2.11.1