[RISCV] Give CSImm12MulBy4 PatLeaf priority over CSImm12MulBy8. NFC

The immediate range check for CSImm12MulBy8 included some values
covered by CSImm12MulBy4. I assume CSImm12MulBy4 had priority due
to pattern order in the td file, but this makes the priority
explicit in the predicate.

diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
index ea9f5f1..33fe909 100644 (file)
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
@@ -218,8 +218,9 @@ def CSImm12MulBy8 : PatLeaf<(imm), [{
   if (!N->hasOneUse())
     return false;
   int64_t C = N->getSExtValue();
-  // Skip if C is simm12 or can be optimized by the PatLeaf AddiPair.
-  return !isInt<13>(C) && isInt<15>(C) && (C & 7) == 0;
+  // Skip if C is simm12 or can be optimized by the PatLeaf AddiPair or
+  // CSImm12MulBy4.
+  return !isInt<14>(C) && isInt<15>(C) && (C & 7) == 0;
 }]>;
 
 def SimmShiftRightBy2XForm : SDNodeXForm<imm, [{