--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lj_opt_sink.c	Thu Jan 22 20:10:30 2026 -0800
@@ -0,0 +1,258 @@
+/*
+** SINK: Allocation Sinking and Store Sinking.
+** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
+*/
+
+#define lj_opt_sink_c
+#define LUA_CORE
+
+#include "lj_obj.h"
+
+#if LJ_HASJIT
+
+#include "lj_ir.h"
+#include "lj_jit.h"
+#include "lj_iropt.h"
+#include "lj_target.h"
+
+/* Some local macros to save typing. Undef'd at the end. */
+#define IR(ref)		(&J->cur.ir[(ref)])
+
+/* Check whether the store ref points to an eligible allocation. */
+static IRIns *sink_checkalloc(jit_State *J, IRIns *irs)
+{
+  IRIns *ir = IR(irs->op1);
+  if (!irref_isk(ir->op2))
+    return NULL;  /* Non-constant key. */
+  if (ir->o == IR_HREFK || ir->o == IR_AREF)
+    ir = IR(ir->op1);
+  else if (!(ir->o == IR_HREF || ir->o == IR_NEWREF ||
+	     ir->o == IR_FREF || ir->o == IR_ADD))
+    return NULL;  /* Unhandled reference type (for XSTORE). */
+  ir = IR(ir->op1);
+  if (!(ir->o == IR_TNEW || ir->o == IR_TDUP || ir->o == IR_CNEW))
+    return NULL;  /* Not an allocation. */
+  return ir;  /* Return allocation. */
+}
+
+/* Recursively check whether a value depends on a PHI. */
+static int sink_phidep(jit_State *J, IRRef ref, int *workp)
+{
+  IRIns *ir = IR(ref);
+  if (!*workp) return 1;  /* Give up and pretend it does. */
+  (*workp)--;
+  if (irt_isphi(ir->t)) return 1;
+  if (ir->op1 >= REF_FIRST && sink_phidep(J, ir->op1, workp)) return 1;
+  if (ir->op2 >= REF_FIRST && sink_phidep(J, ir->op2, workp)) return 1;
+  return 0;
+}
+
+/* Check whether a value is a sinkable PHI or loop-invariant. */
+static int sink_checkphi(jit_State *J, IRIns *ira, IRRef ref)
+{
+  if (ref >= REF_FIRST) {
+    IRIns *ir = IR(ref);
+    if (irt_isphi(ir->t) || (ir->o == IR_CONV && ir->op2 == IRCONV_NUM_INT &&
+			     irt_isphi(IR(ir->op1)->t))) {
+      ira->prev++;
+      return 1;  /* Sinkable PHI. */
+    }
+    /* Otherwise the value must be loop-invariant. */
+    if (ref < J->loopref) {
+      /* Check for PHI dependencies, but give up after reasonable effort. */
+      int work = 64;
+      return !sink_phidep(J, ref, &work);
+    } else {
+      return 0;  /* Loop-variant. */
+    }
+  }
+  return 1;  /* Constant (non-PHI). */
+}
+
+/* Mark non-sinkable allocations using single-pass backward propagation.
+**
+** Roots for the marking process are:
+** - Some PHIs or snapshots (see below).
+** - Non-PHI, non-constant values stored to PHI allocations.
+** - All guards.
+** - Any remaining loads not eliminated by store-to-load forwarding.
+** - Stores with non-constant keys.
+** - All stored values.
+*/
+static void sink_mark_ins(jit_State *J)
+{
+  IRIns *ir, *irlast = IR(J->cur.nins-1);
+  for (ir = irlast ; ; ir--) {
+    switch (ir->o) {
+    case IR_BASE:
+      return;  /* Finished. */
+    case IR_ALOAD: case IR_HLOAD: case IR_XLOAD: case IR_TBAR: case IR_ALEN:
+      irt_setmark(IR(ir->op1)->t);  /* Mark ref for remaining loads. */
+      break;
+    case IR_FLOAD:
+      if (irt_ismarked(ir->t) || ir->op2 == IRFL_TAB_META)
+	irt_setmark(IR(ir->op1)->t);  /* Mark table for remaining loads. */
+      break;
+    case IR_ASTORE: case IR_HSTORE: case IR_FSTORE: case IR_XSTORE: {
+      IRIns *ira = sink_checkalloc(J, ir);
+      if (!ira || (irt_isphi(ira->t) && !sink_checkphi(J, ira, ir->op2)))
+	irt_setmark(IR(ir->op1)->t);  /* Mark ineligible ref. */
+      irt_setmark(IR(ir->op2)->t);  /* Mark stored value. */
+      break;
+      }
+#if LJ_HASFFI
+    case IR_CNEWI:
+      if (irt_isphi(ir->t) &&
+	  (!sink_checkphi(J, ir, ir->op2) ||
+	   (LJ_32 && ir+1 < irlast && (ir+1)->o == IR_HIOP &&
+	    !sink_checkphi(J, ir, (ir+1)->op2))))
+	irt_setmark(ir->t);  /* Mark ineligible allocation. */
+#endif
+      /* fallthrough */
+    case IR_USTORE:
+      irt_setmark(IR(ir->op2)->t);  /* Mark stored value. */
+      break;
+#if LJ_HASFFI
+    case IR_CALLXS:
+#endif
+    case IR_CALLS:
+      irt_setmark(IR(ir->op1)->t);  /* Mark (potentially) stored values. */
+      break;
+    case IR_PHI: {
+      IRIns *irl = IR(ir->op1), *irr = IR(ir->op2);
+      irl->prev = irr->prev = 0;  /* Clear PHI value counts. */
+      if (irl->o == irr->o &&
+	  (irl->o == IR_TNEW || irl->o == IR_TDUP ||
+	   (LJ_HASFFI && (irl->o == IR_CNEW || irl->o == IR_CNEWI))))
+	break;
+      irt_setmark(irl->t);
+      irt_setmark(irr->t);
+      break;
+      }
+    default:
+      if (irt_ismarked(ir->t) || irt_isguard(ir->t)) {  /* Propagate mark. */
+	if (ir->op1 >= REF_FIRST) irt_setmark(IR(ir->op1)->t);
+	if (ir->op2 >= REF_FIRST) irt_setmark(IR(ir->op2)->t);
+      }
+      break;
+    }
+  }
+}
+
+/* Mark all instructions referenced by a snapshot. */
+static void sink_mark_snap(jit_State *J, SnapShot *snap)
+{
+  SnapEntry *map = &J->cur.snapmap[snap->mapofs];
+  MSize n, nent = snap->nent;
+  for (n = 0; n < nent; n++) {
+    IRRef ref = snap_ref(map[n]);
+    if (!irref_isk(ref))
+      irt_setmark(IR(ref)->t);
+  }
+}
+
+/* Iteratively remark PHI refs with differing marks or PHI value counts. */
+static void sink_remark_phi(jit_State *J)
+{
+  IRIns *ir;
+  int remark;
+  do {
+    remark = 0;
+    for (ir = IR(J->cur.nins-1); ir->o == IR_PHI; ir--) {
+      IRIns *irl = IR(ir->op1), *irr = IR(ir->op2);
+      if (!((irl->t.irt ^ irr->t.irt) & IRT_MARK) && irl->prev == irr->prev)
+	continue;
+      remark |= (~(irl->t.irt & irr->t.irt) & IRT_MARK);
+      irt_setmark(IR(ir->op1)->t);
+      irt_setmark(IR(ir->op2)->t);
+    }
+  } while (remark);
+}
+
+/* Sweep instructions and tag sunken allocations and stores. */
+static void sink_sweep_ins(jit_State *J)
+{
+  IRIns *ir, *irbase = IR(REF_BASE);
+  for (ir = IR(J->cur.nins-1) ; ir >= irbase; ir--) {
+    switch (ir->o) {
+    case IR_ASTORE: case IR_HSTORE: case IR_FSTORE: case IR_XSTORE: {
+      IRIns *ira = sink_checkalloc(J, ir);
+      if (ira && !irt_ismarked(ira->t)) {
+	int delta = (int)(ir - ira);
+	ir->prev = REGSP(RID_SINK, delta > 255 ? 255 : delta);
+      } else {
+	ir->prev = REGSP_INIT;
+      }
+      break;
+      }
+    case IR_NEWREF:
+      if (!irt_ismarked(IR(ir->op1)->t)) {
+	ir->prev = REGSP(RID_SINK, 0);
+      } else {
+	irt_clearmark(ir->t);
+	ir->prev = REGSP_INIT;
+      }
+      break;
+#if LJ_HASFFI
+    case IR_CNEW: case IR_CNEWI:
+#endif
+    case IR_TNEW: case IR_TDUP:
+      if (!irt_ismarked(ir->t)) {
+	ir->t.irt &= ~IRT_GUARD;
+	ir->prev = REGSP(RID_SINK, 0);
+	J->cur.sinktags = 1;  /* Signal present SINK tags to assembler. */
+      } else {
+	irt_clearmark(ir->t);
+	ir->prev = REGSP_INIT;
+      }
+      break;
+    case IR_PHI: {
+      IRIns *ira = IR(ir->op2);
+      if (!irt_ismarked(ira->t) &&
+	  (ira->o == IR_TNEW || ira->o == IR_TDUP ||
+	   (LJ_HASFFI && (ira->o == IR_CNEW || ira->o == IR_CNEWI)))) {
+	ir->prev = REGSP(RID_SINK, 0);
+      } else {
+	ir->prev = REGSP_INIT;
+      }
+      break;
+      }
+    default:
+      irt_clearmark(ir->t);
+      ir->prev = REGSP_INIT;
+      break;
+    }
+  }
+  for (ir = IR(J->cur.nk); ir < irbase; ir++) {
+    irt_clearmark(ir->t);
+    ir->prev = REGSP_INIT;
+    /* The false-positive of irt_is64() for ASMREF_L (REF_NIL) is OK here. */
+    if (irt_is64(ir->t) && ir->o != IR_KNULL)
+      ir++;
+  }
+}
+
+/* Allocation sinking and store sinking.
+**
+** 1. Mark all non-sinkable allocations.
+** 2. Then sink all remaining allocations and the related stores.
+*/
+void lj_opt_sink(jit_State *J)
+{
+  const uint32_t need = (JIT_F_OPT_SINK|JIT_F_OPT_FWD|
+			 JIT_F_OPT_DCE|JIT_F_OPT_CSE|JIT_F_OPT_FOLD);
+  if ((J->flags & need) == need &&
+      (J->chain[IR_TNEW] || J->chain[IR_TDUP] ||
+       (LJ_HASFFI && (J->chain[IR_CNEW] || J->chain[IR_CNEWI])))) {
+    if (!J->loopref)
+      sink_mark_snap(J, &J->cur.snap[J->cur.nsnap-1]);
+    sink_mark_ins(J);
+    if (J->loopref)
+      sink_remark_phi(J);
+    sink_sweep_ins(J);
+  }
+}
+
+#undef IR
+
+#endif