[llvm] [Mips] Add r5900 (PlayStation 2 Emotion Engine) FPU Support (PR #178942)

[Matt Arsenault via llvm-commits]

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@@ -554,11 +563,78 @@ SDValue MipsSETargetLowering::LowerOperation(SDValue Op,
   case ISD::VECTOR_SHUFFLE:     return lowerVECTOR_SHUFFLE(Op, DAG);
   case ISD::SELECT:             return lowerSELECT(Op, DAG);
   case ISD::BITCAST:            return lowerBITCAST(Op, DAG);
+  case ISD::FADD:
+  case ISD::FSUB:
+  case ISD::FMUL:
+  case ISD::FDIV:
+  case ISD::FSQRT:
+    return lowerR5900FPOp(Op, DAG);
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arsenm wrote:

I think it would be shorter and nicer if you passed in the LibCall entry to use here, and avoided the switches inside lowerR5900FPOp over the same opcodes 

https://github.com/llvm/llvm-project/pull/178942