[llvm] [RISCV][llvm] Support logical comparison codegen for P extension (PR #174626)

[Craig Topper via llvm-commits]

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@@ -1584,6 +1584,54 @@ let Predicates = [HasStdExtP] in {
   // // splat pattern
   def: Pat<(XLenVecI8VT (splat_vector (XLenVT GPR:$rs2))), (PADD_BS (XLenVT X0), GPR:$rs2)>;
   def: Pat<(XLenVecI16VT (splat_vector (XLenVT GPR:$rs2))), (PADD_HS (XLenVT X0), GPR:$rs2)>;
+
+  // 8/16-bit comparison patterns (result is all 1s or all 0s per element)
+  // a == b
+  def: Pat<(XLenVecI8VT (setcc (XLenVecI8VT GPR:$rs1), (XLenVecI8VT GPR:$rs2), SETEQ)),
+           (PMSEQ_B GPR:$rs1, GPR:$rs2)>;
+  def: Pat<(XLenVecI16VT (setcc (XLenVecI16VT GPR:$rs1), (XLenVecI16VT GPR:$rs2), SETEQ)),
+           (PMSEQ_H GPR:$rs1, GPR:$rs2)>;
+  // a != b => !(a == b)
+  def: Pat<(XLenVecI8VT (setcc (XLenVecI8VT GPR:$rs1), (XLenVecI8VT GPR:$rs2), SETNE)),
+           (XORI (PMSEQ_B GPR:$rs1, GPR:$rs2), -1)>;
+  def: Pat<(XLenVecI16VT (setcc (XLenVecI16VT GPR:$rs1), (XLenVecI16VT GPR:$rs2), SETNE)),
+           (XORI (PMSEQ_H GPR:$rs1, GPR:$rs2), -1)>;
+  // a < b
+  def: Pat<(XLenVecI8VT (setcc (XLenVecI8VT GPR:$rs1), (XLenVecI8VT GPR:$rs2), SETLT)),
+           (PMSLT_B GPR:$rs1, GPR:$rs2)>;
+  def: Pat<(XLenVecI8VT (setcc (XLenVecI8VT GPR:$rs1), (XLenVecI8VT GPR:$rs2), SETULT)),
+           (PMSLTU_B GPR:$rs1, GPR:$rs2)>;
+  def: Pat<(XLenVecI16VT (setcc (XLenVecI16VT GPR:$rs1), (XLenVecI16VT GPR:$rs2), SETLT)),
+           (PMSLT_H GPR:$rs1, GPR:$rs2)>;
+  def: Pat<(XLenVecI16VT (setcc (XLenVecI16VT GPR:$rs1), (XLenVecI16VT GPR:$rs2), SETULT)),
+           (PMSLTU_H GPR:$rs1, GPR:$rs2)>;
+  // a <= b => !(b < a)
+  def: Pat<(XLenVecI8VT (setcc (XLenVecI8VT GPR:$rs1), (XLenVecI8VT GPR:$rs2), SETLE)),
+           (XORI (PMSLT_B GPR:$rs2, GPR:$rs1), -1)>;
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topperc wrote:

The rs1 and rs2 names belong to the instruction. They should always be `(PMSLT_B GPR:$rs1, GPR:$rs2)`. The input pattern is where the swap should occur.

https://github.com/llvm/llvm-project/pull/174626