[llvm] [NVPTX] Add Intrinsics for discard.* (PR #128404)

[Durgadoss R via llvm-commits]

================
@@ -5043,6 +5043,15 @@ def int_nvvm_prefetch_global_L2_evict_last: Intrinsic<[], [llvm_global_ptr_ty],
 def int_nvvm_prefetchu_L1 : Intrinsic<[], [llvm_ptr_ty],
   [IntrArgMemOnly, ReadOnly<ArgIndex<0>>, NoCapture<ArgIndex<0>>]>;
 
+// Intrinsics for discard
+def int_nvvm_discard_global_L2 : DefaultAttrsIntrinsic<[], 
+    [llvm_global_ptr_ty, llvm_i64_ty], [IntrArgMemOnly, ReadOnly<ArgIndex<0>>, 
----------------
durga4github wrote:

> Another concern is that we will invalidate `[a .. a + (size - 1)]` I'm not quite sure whether LLVM tracks the amount of data accessed via a pointer. If it does, then we may need to apply `hasSideEffects` to let LLVM know that we're messing with more than the pointee-type-sized chunk of memory.

Artem, I believe you meant, "If it does not", right?

https://github.com/llvm/llvm-project/pull/128404