AMDGPU: Use umin in set.rounding expansion

Addresses comment from llvm#88587

Author: arsenm

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -4098,19 +4098,15 @@ SDValue SITargetLowering::lowerSET_ROUNDING(SDValue Op,
       // TODO: SimplifyDemandedBits on the setreg source here can likely reduce
       // the table extracted bits into inline immediates.
     } else {
-      // is_standard = value < 4;
-      // table_index = is_standard ? value : (value - 4)
+      // table_index = umin(value, value - 4)
       // MODE.fp_round = (bit_table >> (table_index << 2)) & 0xf
       SDValue BitTable =
           DAG.getConstant(AMDGPU::FltRoundToHWConversionTable, SL, MVT::i64);
 
       SDValue Four = DAG.getConstant(4, SL, MVT::i32);
-      SDValue IsStandardValue =
-          DAG.getSetCC(SL, MVT::i1, NewMode, Four, ISD::SETULT);
       SDValue OffsetEnum = DAG.getNode(ISD::SUB, SL, MVT::i32, NewMode, Four);
-
-      SDValue IndexVal = DAG.getNode(ISD::SELECT, SL, MVT::i32, IsStandardValue,
-                                     NewMode, OffsetEnum);
+      SDValue IndexVal =
+          DAG.getNode(ISD::UMIN, SL, MVT::i32, NewMode, OffsetEnum);
 
       SDValue Two = DAG.getConstant(2, SL, MVT::i32);
       SDValue RoundModeTimesNumBits =