[llvm] [Xtensa] Implement lowering SELECT_CC/BRCC for Xtensa FP Option. (PR #145544)

[Andrei Safronov via llvm-commits]

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@@ -841,21 +847,97 @@ static unsigned getBranchOpcode(ISD::CondCode Cond) {
   }
 }
 
+static std::pair<unsigned, unsigned> getFPBranchKind(ISD::CondCode Cond) {
+  unsigned BrKind;
+  unsigned CmpKind;
+
+  switch (Cond) {
+  case ISD::SETUNE:
+    BrKind = Xtensa::BF;
+    CmpKind = Xtensa::OEQ_S;
+    break;
+  case ISD::SETUO:
+    BrKind = Xtensa::BT;
+    CmpKind = Xtensa::UN_S;
+    break;
+  case ISD::SETO:
+    BrKind = Xtensa::BF;
+    CmpKind = Xtensa::UN_S;
+    break;
+  case ISD::SETUEQ:
+    BrKind = Xtensa::BT;
+    CmpKind = Xtensa::UEQ_S;
+    break;
+  case ISD::SETULE:
+    BrKind = Xtensa::BT;
+    CmpKind = Xtensa::ULE_S;
+    break;
+  case ISD::SETULT:
+    BrKind = Xtensa::BT;
+    CmpKind = Xtensa::ULT_S;
+    break;
+  case ISD::SETEQ:
+  case ISD::SETOEQ:
+    BrKind = Xtensa::BT;
+    CmpKind = Xtensa::OEQ_S;
+    break;
+  case ISD::SETNE:
+    BrKind = Xtensa::BF;
+    CmpKind = Xtensa::OEQ_S;
+    break;
+  case ISD::SETLE:
+  case ISD::SETOLE:
+    BrKind = Xtensa::BT;
+    CmpKind = Xtensa::OLE_S;
+    break;
+  case ISD::SETLT:
+  case ISD::SETOLT:
+    BrKind = Xtensa::BT;
+    CmpKind = Xtensa::OLT_S;
+    break;
+  case ISD::SETGE:
+    BrKind = Xtensa::BF;
+    CmpKind = Xtensa::OLT_S;
+    break;
+  case ISD::SETGT:
+    BrKind = Xtensa::BF;
+    CmpKind = Xtensa::OLE_S;
+    break;
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andreisfr wrote:

fxied.

https://github.com/llvm/llvm-project/pull/145544