[PATCH] D143134: [AMDGPU][SDAG] attempt to custom legalize uaddo/usubo for long operands

[Alexander via Phabricator via llvm-commits]

alex-t added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp:906
+  
+  if (IsVALU) {
+    unsigned Opc = IsAdd ? AMDGPU::V_ADDC_U32_e64 
----------------
What if N is not divergent but has just one user selected to VALU and has yet 10 SALU users? Would this still be optimal?


================
Comment at: llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp:945
   } else {
-    unsigned Opc = N->getOpcode() == ISD::UADDO ? AMDGPU::S_UADDO_PSEUDO
-                                                : AMDGPU::S_USUBO_PSEUDO;
+    unsigned Opc = IsAdd ? AMDGPU::S_UADDO_PSEUDO
+                         : AMDGPU::S_USUBO_PSEUDO;
----------------
Does this really belong to this change?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D143134/new/

https://reviews.llvm.org/D143134