[llvm] e328385 - Revert "[RISCV] Make the operand order for RISCVISD::FSL(W)/FSR(W) match the instruction register numbering."

Craig Topper via llvm-commits llvm-commits at lists.llvm.org
Tue Jan 18 10:36:25 PST 2022


Author: Craig Topper
Date: 2022-01-18T10:36:03-08:00
New Revision: e32838573929ac85fc4df3058593798d10ce4cd2

URL: https://github.com/llvm/llvm-project/commit/e32838573929ac85fc4df3058593798d10ce4cd2
DIFF: https://github.com/llvm/llvm-project/commit/e32838573929ac85fc4df3058593798d10ce4cd2.diff

LOG: Revert "[RISCV] Make the operand order for RISCVISD::FSL(W)/FSR(W) match the instruction register numbering."

This reverts commit b634f8a663d56877663f5224a785d9f0263c4176.

I broke the SimplifyDemandedBits code, but we don't have tests.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    llvm/lib/Target/RISCV/RISCVISelLowering.h
    llvm/lib/Target/RISCV/RISCVInstrInfoZb.td

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index b0e5d735b81e3..39ecf0a3dbedf 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2795,24 +2795,12 @@ SDValue RISCVTargetLowering::LowerOperation(SDValue Op,
     if (Op.getOperand(2).getOpcode() == ISD::Constant)
       return Op;
     // FSL/FSR take a log2(XLen)+1 bit shift amount but XLenVT FSHL/FSHR only
-    // use log(XLen) bits. Mask the shift amount accordingly to prevent
-    // accidentally setting the extra bit.
+    // use log(XLen) bits. Mask the shift amount accordingly.
     unsigned ShAmtWidth = Subtarget.getXLen() - 1;
     SDValue ShAmt = DAG.getNode(ISD::AND, DL, VT, Op.getOperand(2),
                                 DAG.getConstant(ShAmtWidth, DL, VT));
-    // fshl and fshr concatenate their operands in the same order. fsr and fsl
-    // instruction use 
diff erent orders. fshl will return its first operand for
-    // shift of zero, fshr will return its second operand. fsl and fsr both
-    // return rs1 so the ISD nodes need to have 
diff erent operand orders.
-    // Shift amount is in rs2.
-    SDValue Op0 = Op.getOperand(0);
-    SDValue Op1 = Op.getOperand(1);
-    unsigned Opc = RISCVISD::FSL;
-    if (Op.getOpcode() == ISD::FSHR) {
-      std::swap(Op0, Op1);
-      Opc = RISCVISD::FSR;
-    }
-    return DAG.getNode(Opc, DL, VT, Op0, Op1, ShAmt);
+    unsigned Opc = Op.getOpcode() == ISD::FSHL ? RISCVISD::FSL : RISCVISD::FSR;
+    return DAG.getNode(Opc, DL, VT, Op.getOperand(0), Op.getOperand(1), ShAmt);
   }
   case ISD::TRUNCATE: {
     SDLoc DL(Op);
@@ -6244,23 +6232,15 @@ void RISCVTargetLowering::ReplaceNodeResults(SDNode *N,
         DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i64, N->getOperand(0));
     SDValue NewOp1 =
         DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i64, N->getOperand(1));
-    SDValue NewShAmt =
+    SDValue NewOp2 =
         DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i64, N->getOperand(2));
     // FSLW/FSRW take a 6 bit shift amount but i32 FSHL/FSHR only use 5 bits.
-    // Mask the shift amount to 5 bits to prevent accidentally setting bit 5.
-    NewShAmt = DAG.getNode(ISD::AND, DL, MVT::i64, NewShAmt,
-                           DAG.getConstant(0x1f, DL, MVT::i64));
-    // fshl and fshr concatenate their operands in the same order. fsrw and fslw
-    // instruction use 
diff erent orders. fshl will return its first operand for
-    // shift of zero, fshr will return its second operand. fsl and fsr both
-    // return rs1 so the ISD nodes need to have 
diff erent operand orders.
-    // Shift amount is in rs2.
-    unsigned Opc = RISCVISD::FSLW;
-    if (N->getOpcode() == ISD::FSHR) {
-      std::swap(NewOp0, NewOp1);
-      Opc = RISCVISD::FSRW;
-    }
-    SDValue NewOp = DAG.getNode(Opc, DL, MVT::i64, NewOp0, NewOp1, NewShAmt);
+    // Mask the shift amount to 5 bits.
+    NewOp2 = DAG.getNode(ISD::AND, DL, MVT::i64, NewOp2,
+                         DAG.getConstant(0x1f, DL, MVT::i64));
+    unsigned Opc =
+        N->getOpcode() == ISD::FSHL ? RISCVISD::FSLW : RISCVISD::FSRW;
+    SDValue NewOp = DAG.getNode(Opc, DL, MVT::i64, NewOp0, NewOp1, NewOp2);
     Results.push_back(DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, NewOp));
     break;
   }
@@ -7296,9 +7276,9 @@ SDValue RISCVTargetLowering::PerformDAGCombine(SDNode *N,
   case RISCVISD::FSL:
   case RISCVISD::FSR: {
     // Only the lower log2(Bitwidth)+1 bits of the the shift amount are read.
-    unsigned BitWidth = N->getOperand(1).getValueSizeInBits();
+    unsigned BitWidth = N->getOperand(2).getValueSizeInBits();
     assert(isPowerOf2_32(BitWidth) && "Unexpected bit width");
-    if (SimplifyDemandedLowBitsHelper(1, Log2_32(BitWidth) + 1))
+    if (SimplifyDemandedLowBitsHelper(2, Log2_32(BitWidth) + 1))
       return SDValue(N, 0);
     break;
   }
@@ -7307,8 +7287,8 @@ SDValue RISCVTargetLowering::PerformDAGCombine(SDNode *N,
     // Only the lower 32 bits of Values and lower 6 bits of shift amount are
     // read.
     if (SimplifyDemandedLowBitsHelper(0, 32) ||
-        SimplifyDemandedLowBitsHelper(2, 32) ||
-        SimplifyDemandedLowBitsHelper(1, 6))
+        SimplifyDemandedLowBitsHelper(1, 32) ||
+        SimplifyDemandedLowBitsHelper(2, 6))
       return SDValue(N, 0);
     break;
   }

diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.h b/llvm/lib/Target/RISCV/RISCVISelLowering.h
index 76b778831fae0..cd423c9ecca09 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -63,11 +63,11 @@ enum NodeType : unsigned {
   CLZW,
   CTZW,
   // RV64IB/RV32IB funnel shifts, with the semantics of the named RISC-V
-  // instructions. Operand order is rs1, rs3, rs2/shamt.
+  // instructions, but the same operand order as fshl/fshr intrinsics.
   FSR,
   FSL,
-  // RV64IB funnel shifts, with the semantics of the named RISC-V instructions.
-  // Operand order is rs1, rs3, rs2/shamt.
+  // RV64IB funnel shifts, with the semantics of the named RISC-V instructions,
+  // but the same operand order as fshl/fshr intrinsics.
   FSRW,
   FSLW,
   // FPR<->GPR transfer operations when the FPR is smaller than XLEN, needed as

diff  --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
index 74f617c8333a7..c2e7217df30fe 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
@@ -901,16 +901,16 @@ def : Pat<(select GPR:$rs2, GPR:$rs1, GPR:$rs3),
           (CMOV GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
 } // Predicates = [HasStdExtZbt]
 
+// fshl and fshr concatenate their operands in the same order. fsr and fsl
+// instruction use 
diff erent orders. fshl will return its first operand for
+// shift of zero, fshr will return its second operand. fsl and fsr both return
+// $rs1 so the patterns need to have 
diff erent operand orders.
 let Predicates = [HasStdExtZbt] in {
 def : Pat<(riscv_fsl GPR:$rs1, GPR:$rs3, GPR:$rs2),
           (FSL GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
-def : Pat<(riscv_fsr GPR:$rs1, GPR:$rs3, GPR:$rs2),
+def : Pat<(riscv_fsr GPR:$rs3, GPR:$rs1, GPR:$rs2),
           (FSR GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
 
-// fshl and fshr concatenate their operands in the same order. fsr and fsl
-// instruction use 
diff erent orders. fshl will return its first operand for
-// shift of zero, fshr will return its second operand. fsl and fsr both return
-// $rs1 so the patterns need to have 
diff erent operand orders.
 def : Pat<(fshr GPR:$rs3, GPR:$rs1, uimmlog2xlen:$shamt),
           (FSRI GPR:$rs1, GPR:$rs3, uimmlog2xlen:$shamt)>;
 // We can use FSRI for fshl by immediate if we subtract the immediate from
@@ -1090,12 +1090,10 @@ def : PatGprImm<riscv_gorcw, GORCIW, uimm5>;
 let Predicates = [HasStdExtZbt, IsRV64] in {
 def : Pat<(riscv_fslw GPR:$rs1, GPR:$rs3, GPR:$rs2),
           (FSLW GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
-def : Pat<(riscv_fsrw GPR:$rs1, GPR:$rs3, GPR:$rs2),
+def : Pat<(riscv_fsrw GPR:$rs3, GPR:$rs1, GPR:$rs2),
           (FSRW GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
-def : Pat<(riscv_fsrw GPR:$rs1, GPR:$rs3, uimm5:$shamt),
+def : Pat<(riscv_fsrw GPR:$rs3, GPR:$rs1, uimm5:$shamt),
           (FSRIW GPR:$rs1, GPR:$rs3, uimm5:$shamt)>;
-// We can use FSRIW for FSLW by immediate if we subtract the immediate from
-// 32 and swap the operands.
 def : Pat<(riscv_fslw GPR:$rs3, GPR:$rs1, uimm5:$shamt),
           (FSRIW GPR:$rs1, GPR:$rs3, (ImmSubFrom32 uimm5:$shamt))>;
 } // Predicates = [HasStdExtZbt, IsRV64]


        


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