From 9e41531b0803ee2c551400ffbd15e74760135c5d Mon Sep 17 00:00:00 2001
From: Max Bernstein <max@bernsteinbear.com>
Date: Tue, 28 Nov 2023 14:06:18 -0500
Subject: [PATCH] wip what is going on

---
 library/_compiler.py |  2 +-
 runtime/bytecode.cpp | 15 ++++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/library/_compiler.py b/library/_compiler.py
index 6dfc1324b..87de55cd7 100644
--- a/library/_compiler.py
+++ b/library/_compiler.py
@@ -297,7 +297,7 @@ def process_one_block(block, modify=False):
             self.entry.insts = deletes + self.entry.insts
 
     def getCode(self):
-        self.optimizeLoadFast()
+        # self.optimizeLoadFast()
         return super().getCode()
 
 
diff --git a/runtime/bytecode.cpp b/runtime/bytecode.cpp
index 54dd51abf..4f6ae5b17 100644
--- a/runtime/bytecode.cpp
+++ b/runtime/bytecode.cpp
@@ -372,7 +372,7 @@ static uword runDefiniteAssignmentOpcode(Bytecode op, uword arg,
   switch (op) {
     case STORE_FAST: {
       DCHECK_INDEX(arg, kBitsPerWord);
-      defined |= uword{1} << arg;
+      defined |= (uword{1} << arg);
       break;
     }
     case DELETE_FAST: {
@@ -431,20 +431,29 @@ static void analyzeDefiniteAssignment(Thread* thread,
   defined_in[0] = setBottomNBits(function.totalArgs());
   // Run until fixpoint.
   word num_iterations = 0;
-  for (bool changed = true; changed;) {
+  for (bool changed = true; changed && num_iterations < 100;) {
     changed = false;
     for (const Edge& edge : edges) {
       Bytecode op = rewrittenBytecodeOpAt(bytecode, edge.start_index);
+      fprintf(stderr, "processing op %s\n", kBytecodeNames[op]);
       DCHECK(op != RETURN_VALUE, "RETURN_VALUE should not have any edges");
       uword arg = rewrittenBytecodeArgAt(bytecode, edge.start_index);
       // TODO(max): Compute meet of previous edges here
+      // uword defined_before = top;
+      // for (const Edge& edge2 : edges) {
+      //   if (edge2.end_index == edge.start_index) {
+      //     defined_before = meet(defined_before, defined_out[edge2.start_index]);
+      //   }
+      // }
       uword defined_before = defined_in[edge.start_index];
       uword defined_after =
           runDefiniteAssignmentOpcode(op, arg, defined_before);
       if (defined_after != defined_before) {
         changed = true;
       }
+      // TODO(max): Use meet
       defined_out[edge.end_index] = defined_after;
+      defined_in[edge.end_index] = defined_after;
     }
     num_iterations++;
   }
@@ -454,7 +463,7 @@ static void analyzeDefiniteAssignment(Thread* thread,
     word idx = i;
     BytecodeOp op = nextBytecodeOp(bytecode, &i);
     fprintf(stderr, "%04lx %24s %4d (", idx, kBytecodeNames[op.bc], op.arg);
-    printBits(stderr, defined_in[idx]);
+    printBits(stderr, defined_out[idx]);
     fprintf(stderr, ")\n");
   }
   DTRACE_PROBE1(python, DefiniteAssignmentIterations, num_iterations);