[PATCH] D140988: [SystemZ] Implement lowering of GET_ROUNDING

[Tulio Magno Quites Machado Filho via Phabricator via llvm-commits]

tuliom marked 3 inline comments as done.
tuliom added inline comments.


================
Comment at: llvm/lib/Target/SystemZ/SystemZISelLowering.cpp:9085
+      DAG.getNode((VT.getSizeInBits() < 16 ? ISD::TRUNCATE : ISD::ZERO_EXTEND),
+                  dl, VT, RetVal);
+
----------------
tuliom wrote:
> uweigand wrote:
> > Since we're doing the computation in `i32`, shouldn't this be a `TRUNCATE` for all sizes < 32 ?   Also, if the size is exactly 32, we don't need either truncate or extend (not sure if the extend gets optimized away?).
> Oops. That's correct.
> No, it does not get optimized away.
> No, it does not get optimized away.

Let me correct myself: in a way, it does get optimized away.
But , AFAIU, the LLGFR is needed after RXSBG anyway.
You can see the generated code in the updated test.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D140988/new/

https://reviews.llvm.org/D140988