From e091baf7a8258359b4e74ca4320f31865a331b31 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Sun, 30 Apr 2017 23:59:16 +0200
Subject: [PATCH] Add FOLD rules for mixed BAND/BOR with constants.

---
 src/lj_opt_fold.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/src/lj_opt_fold.c b/src/lj_opt_fold.c
index 362737d140..a4272cd4ee 100644
--- a/src/lj_opt_fold.c
+++ b/src/lj_opt_fold.c
@@ -1619,6 +1619,47 @@ LJFOLDF(simplify_andk_shiftk)
   return NEXTFOLD;
 }
 
+LJFOLD(BAND BOR KINT)
+LJFOLD(BOR BAND KINT)
+LJFOLDF(simplify_andor_k)
+{
+  IRIns *irk = IR(fleft->op2);
+  PHIBARRIER(fleft);
+  if (irk->o == IR_KINT) {
+    int32_t k = kfold_intop(irk->i, fright->i, (IROp)fins->o);
+    /* (i | k1) & k2 ==> i & k2, if (k1 & k2) == 0. */
+    /* (i & k1) | k2 ==> i | k2, if (k1 | k2) == -1. */
+    if (k == (fins->o == IR_BAND ? 0 : -1)) {
+      fins->op1 = fleft->op1;
+      return RETRYFOLD;
+    }
+  }
+  return NEXTFOLD;
+}
+
+LJFOLD(BAND BOR KINT64)
+LJFOLD(BOR BAND KINT64)
+LJFOLDF(simplify_andor_k64)
+{
+#if LJ_HASFFI
+  IRIns *irk = IR(fleft->op2);
+  PHIBARRIER(fleft);
+  if (irk->o == IR_KINT64) {
+    uint64_t k = kfold_int64arith(ir_k64(irk)->u64,
+				  ir_k64(fright)->u64, (IROp)fins->o);
+    /* (i | k1) & k2 ==> i & k2, if (k1 & k2) == 0. */
+    /* (i & k1) | k2 ==> i | k2, if (k1 | k2) == -1. */
+    if (k == (fins->o == IR_BAND ? (uint64_t)0 : ~(uint64_t)0)) {
+      fins->op1 = fleft->op1;
+      return RETRYFOLD;
+    }
+  }
+  return NEXTFOLD;
+#else
+  UNUSED(J); lua_assert(0); return FAILFOLD;
+#endif
+}
+
 /* -- Reassociation ------------------------------------------------------- */
 
 LJFOLD(ADD ADD KINT)