AMDGPU/GlobalISel: Lower 64-bit uaddo/usubo

Summary: Add more test cases for signed and unsigned add/sub with overflow.

Reviewers: arsenm, rampitec, kerbowa

Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, rovka, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75051

Author: jayfoad

llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp

@@ -331,8 +331,9 @@ AMDGPULegalizerInfo::AMDGPULegalizerInfo(const GCNSubtarget &ST_,
   getActionDefinitionsBuilder({G_UADDO, G_USUBO,
                                G_UADDE, G_SADDE, G_USUBE, G_SSUBE})
     .legalFor({{S32, S1}, {S32, S32}})
-    .clampScalar(0, S32, S32)
-    .scalarize(0); // TODO: Implement.
+    .minScalar(0, S32)
+    // TODO: .scalarize(0)
+    .lower();
 
   getActionDefinitionsBuilder(G_BITCAST)
     // Don't worry about the size constraint.