[AMDGPU] Fix comments about afn and arcp in fast unsafe fdiv handling (#68982)

Author: jayfoad

llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp

@@ -4641,8 +4641,8 @@ bool AMDGPULegalizerInfo::legalizeFastUnsafeFDIV(MachineInstr &MI,
     }
   }
 
-  // For f16 require arcp only.
-  // For f32 require afn+arcp.
+  // For f16 require afn or arcp.
+  // For f32 require afn.
   if (!AllowInaccurateRcp && (ResTy != LLT::scalar(16) ||
                               !MI.getFlag(MachineInstr::FmArcp)))
     return false;

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -9577,8 +9577,8 @@ SDValue SITargetLowering::lowerFastUnsafeFDIV(SDValue Op,
     }
   }
 
-  // For f16 require arcp only.
-  // For f32 require afn+arcp.
+  // For f16 require afn or arcp.
+  // For f32 require afn.
   if (!AllowInaccurateRcp && (VT != MVT::f16 || !Flags.hasAllowReciprocal()))
     return SDValue();