[RISCV] Rename RISCVISD::ABSW->NEGW_MAX. NFC (#164909)

This matches what it expands to. The P extension adds a proper ABSW
instruction so being precise is important to avoid confusion.

Author: topperc

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -14797,7 +14797,7 @@ void RISCVTargetLowering::ReplaceNodeResults(SDNode *N,
       // to NEGW+MAX here requires a Freeze which breaks ComputeNumSignBits.
       SDValue Src = DAG.getNode(ISD::SIGN_EXTEND, DL, MVT::i64,
                                 N->getOperand(0));
-      SDValue Abs = DAG.getNode(RISCVISD::ABSW, DL, MVT::i64, Src);
+      SDValue Abs = DAG.getNode(RISCVISD::NEGW_MAX, DL, MVT::i64, Src);
       Results.push_back(DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, Abs));
       return;
     }
@@ -21813,7 +21813,7 @@ unsigned RISCVTargetLowering::ComputeNumSignBitsForTargetNode(
     // Output is either all zero or operand 0. We can propagate sign bit count
     // from operand 0.
     return DAG.ComputeNumSignBits(Op.getOperand(0), DemandedElts, Depth + 1);
-  case RISCVISD::ABSW: {
+  case RISCVISD::NEGW_MAX: {
     // We expand this at isel to negw+max. The result will have 33 sign bits
     // if the input has at least 33 sign bits.
     unsigned Tmp =

llvm/lib/Target/RISCV/RISCVInstrInfoZb.td

@@ -51,7 +51,7 @@ def riscv_zip     : RVSDNode<"ZIP",     SDTIntUnaryOp>;
 def riscv_unzip   : RVSDNode<"UNZIP",   SDTIntUnaryOp>;
 
 // RV64IZbb absolute value for i32. Expanded to (max (negw X), X) during isel.
-def riscv_absw    : RVSDNode<"ABSW",    SDTIntUnaryOp>;
+def riscv_negw_max : RVSDNode<"NEGW_MAX",    SDTIntUnaryOp>;
 
 // Scalar cryptography
 def riscv_clmul   : RVSDNode<"CLMUL",   SDTIntBinOp>;
@@ -610,7 +610,7 @@ def : PatGpr<riscv_clzw, CLZW>;
 def : PatGpr<riscv_ctzw, CTZW>;
 def : Pat<(i64 (ctpop (i64 (zexti32 (i64 GPR:$rs1))))), (CPOPW GPR:$rs1)>;
 
-def : Pat<(i64 (riscv_absw GPR:$rs1)),
+def : Pat<(i64 (riscv_negw_max GPR:$rs1)),
           (MAX GPR:$rs1, (XLenVT (SUBW (XLenVT X0), GPR:$rs1)))>;
 } // Predicates = [HasStdExtZbb, IsRV64]