[llvm-commits] CVS: reopt/lib/TraceToFunction/TraceToFunction.cpp

[Brian Gaeke]

Changes in directory reopt/lib/TraceToFunction:

TraceToFunction.cpp updated: 1.56 -> 1.57

---
Log message:

Three important changes regarding trace entry-BB Phi nodes:
1) In DEBUG mode, change their names to reflect their special status, and add
better debug messages.
2) Assert that they are live-in (fixing a longstanding FIXME).
3) Rewrite their off-trace incoming values to be the argument of the TraceFn
which carries their live-in value.


---
Diffs of the changes:  (+28 -12)

Index: reopt/lib/TraceToFunction/TraceToFunction.cpp
diff -u reopt/lib/TraceToFunction/TraceToFunction.cpp:1.56 reopt/lib/TraceToFunction/TraceToFunction.cpp:1.57
--- reopt/lib/TraceToFunction/TraceToFunction.cpp:1.56	Fri May 21 15:54:44 2004
+++ reopt/lib/TraceToFunction/TraceToFunction.cpp	Sat May 22 01:56:39 2004
@@ -546,26 +546,42 @@
   if (srcB == T.getEntryBasicBlock ()) {
     BasicBlock *EntryFixup = new BasicBlock ("entryfixup", F, dstB);
     EntryFixup->getInstList ().push_back (new BranchInst (dstB));
-    // Replace the references to the trace's predecessor with a
-    // reference to EntryFixup now. This is kind of a dodge because we
-    // don't have a pointer to the trace's predecessor, so we have
-    // to guess which one it is. Assume it's any phi value source in
-    // the entry BB which is not in the trace.
+    // Rewrite phi nodes in the entry basic block, which carry values
+    // that are live-in to the trace: Off-trace phi sources must be
+    // rewritten to take their value from the entryfixup block, and get
+    // their value from the argument which carries the live-in value.
     for (BasicBlock::iterator BI = srcB->begin ();
-         PHINode *PN = dyn_cast<PHINode> (BI); ++BI)
-      for (unsigned i = 0; i < PN->getNumIncomingValues (); ++i) {
+         PHINode *oldPN = dyn_cast<PHINode> (BI); ++BI) {
+      DEBUG (std::cerr << "fixupFunctionBodyBB: Changing name of trace"
+        << " entry block Phi node:\n" << O2CMap[oldPN] << " to "
+        << O2CMap[oldPN]->getName() << ".phifixup\n";
+        O2CMap[oldPN]->setName (O2CMap[oldPN]->getName () + ".phifixup"));
+      assert (TF->LiveInSet.find (oldPN) != TF->LiveInSet.end ()
+              && "Phi nodes in trace entry BB must be live-in");
+      unsigned argNum = TF->LiveInToParameterMap [oldPN];
+      Argument *phiLiveIn = getFunctionArg (F, argNum);
+      for (unsigned i = 0; i < oldPN->getNumIncomingValues (); ++i) {
         // Fold Phi sources which come from FLI blocks
-        BasicBlock *phiSource = PN->getIncomingBlock (i);
+        BasicBlock *phiSource = oldPN->getIncomingBlock (i);
         if (BasicBlock *realSource = getFLIEdgeSource (phiSource))
           phiSource = realSource;
         if (!T.contains (phiSource)) {
-          // FIXME: Assert that O2CMap[PN]'s value i is live in.
-          Value *V = O2CMap[PN];
+          Value *V = O2CMap[oldPN];
           assert (V && isa<PHINode> (V)
                   && "Clone of PHINode from trace entry BB missing or mangled");
-          cast<PHINode> (V)->setIncomingBlock (i, EntryFixup);
+          PHINode *newPN = cast<PHINode> (V);
+          DEBUG (std::cerr << "fixupFunctionBodyBB: Changing incoming block "
+            << i << " of trace entry block Phi node:\n" << *newPN << " from "
+            << newPN->getIncomingBlock (i)->getName () << " to entry-fixup "
+            << "block, and incoming value to argument " << argNum << " (";
+            WriteAsOperand (std::cerr, phiLiveIn, true, true,
+                            TF->TraceFn->getParent ());
+            std::cerr << ")\n");
+          newPN->setIncomingBlock (i, EntryFixup);
+          newPN->setIncomingValue (i, phiLiveIn);
         }
-     }
+      }
+    }
   }
 
   // If srcB contains a trace-exiting branch B, fix up B's clone in