[compiler] Error out after writing the LLVM file to disk, to let users debug it

Author: giordano

src/compiler/codelet.jl

@@ -236,10 +236,6 @@ function __build_codelet(graph::Poplar.GraphAllocated, kernel, name::String, ori
                       "_llvm_colossus_urand32" => "llvm.colossus.urand32",
                       "_llvm_colossus_urand64" => "llvm.colossus.urand64",
                       )
-    # Do not allow references to literal pointers, which are likely to be invalid on the IPU
-    if contains(llvm_ir, r"inttoptr +\(i64 +\d+")
-        error("LLVM IR generated for codelet $(name) contains a reference to a literal pointer")
-    end
 
     method = methods(origKernel)[end]
     args = method.sig.parameters[2:end]
@@ -261,6 +257,11 @@ function __build_codelet(graph::Poplar.GraphAllocated, kernel, name::String, ori
         input_file = joinpath(KEEP_LLVM_FILES[] ? "" : dir, "$(name).ll")
         write(input_file, llvm_ir)
 
+        # Do not allow references to literal pointers, which are likely to be invalid on the IPU
+        if contains(llvm_ir, r"inttoptr +\(i64 +\d+")
+            error("LLVM IR generated for codelet $(name) contains a reference to a literal pointer")
+        end
+
         # Unless `POPC_FLAGS[]` already sets `-target`, if we have calls to Colossus
         # intrinsics we can't target the IPU model on CPU (the `cpu` target), so in that
         # case we compile only for `ipu1,ipu2`.