1 files changed, 21 insertions, 18 deletions
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoM.td b/llvm/lib/Target/RISCV/RISCVInstrInfoM.td
index b8b56ac3dc6..e75151ba99c 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoM.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoM.td
@@ -12,6 +12,14 @@
 //===----------------------------------------------------------------------===//
 
 //===----------------------------------------------------------------------===//
+// RISC-V specific DAG Nodes.
+//===----------------------------------------------------------------------===//
+
+def riscv_divw  : SDNode<"RISCVISD::DIVW",  SDTIntBinOp>;
+def riscv_divuw : SDNode<"RISCVISD::DIVUW", SDTIntBinOp>;
+def riscv_remuw : SDNode<"RISCVISD::REMUW", SDTIntBinOp>;
+
+//===----------------------------------------------------------------------===//
 // Instructions
 //===----------------------------------------------------------------------===//
 
@@ -52,18 +60,19 @@ def : PatGprGpr<urem, REMU>;
 let Predicates = [HasStdExtM, IsRV64] in {
 def : Pat<(sext_inreg (mul GPR:$rs1, GPR:$rs2), i32),
           (MULW GPR:$rs1, GPR:$rs2)>;
-def : Pat<(sext_inreg (sdiv (sexti32 GPR:$rs1),
-                            (sexti32 GPR:$rs2)), i32),
-          (DIVW GPR:$rs1, GPR:$rs2)>;
-def : Pat<(zexti32 (sdiv (sexti32 GPR:$rs1),
-                         (sexti32 GPR:$rs2))),
-          (SRLI (SLLI (DIVW GPR:$rs1, GPR:$rs2), 32), 32)>;
-def : Pat<(sext_inreg (udiv (zexti32 GPR:$rs1), (zexti32 GPR:$rs2)), i32),
-          (DIVUW GPR:$rs1, GPR:$rs2)>;
-// It's cheaper to perform a divuw and zero-extend the result than to
-// zero-extend both inputs to a udiv.
-def : Pat<(udiv (and GPR:$rs1, 0xffffffff), (and GPR:$rs2, 0xffffffff)),
-          (SRLI (SLLI (DIVUW GPR:$rs1, GPR:$rs2), 32), 32)>;
+
+def : PatGprGpr<riscv_divw, DIVW>;
+def : PatGprGpr<riscv_divuw, DIVUW>;
+def : PatGprGpr<riscv_remuw, REMUW>;
+
+// Handle the specific cases where using DIVU/REMU would be correct and result
+// in fewer instructions than emitting DIVUW/REMUW then zero-extending the
+// result.
+def : Pat<(zexti32 (riscv_divuw (zexti32 GPR:$rs1), (zexti32 GPR:$rs2))),
+          (DIVU GPR:$rs1, GPR:$rs2)>;
+def : Pat<(zexti32 (riscv_remuw (zexti32 GPR:$rs1), (zexti32 GPR:$rs2))),
+          (REMU GPR:$rs1, GPR:$rs2)>;
+
 // Although the sexti32 operands may not have originated from an i32 srem,
 // this pattern is safe as it is impossible for two sign extended inputs to
 // produce a result where res[63:32]=0 and res[31]=1.
@@ -72,10 +81,4 @@ def : Pat<(srem (sexti32 GPR:$rs1), (sexti32 GPR:$rs2)),
 def : Pat<(sext_inreg (srem (sexti32 GPR:$rs1),
                             (sexti32 GPR:$rs2)), i32),
           (REMW GPR:$rs1, GPR:$rs2)>;
-def : Pat<(sext_inreg (urem (zexti32 GPR:$rs1), (zexti32 GPR:$rs2)), i32),
-          (REMUW GPR:$rs1, GPR:$rs2)>;
-// It's cheaper to perform a remuw and zero-extend the result than to
-// zero-extend both inputs to a urem.
-def : Pat<(urem (and GPR:$rs1, 0xffffffff), (and GPR:$rs2, 0xffffffff)),
-          (SRLI (SLLI (REMUW GPR:$rs1, GPR:$rs2), 32), 32)>;
 } // Predicates = [HasStdExtM, IsRV64]