Added documentation. Constant fold terminators.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index ba271b4e26fe8ec7ba4fe1c00f5a1ad99440efdf..7273aec3f4d7301dbe3cb20925e21776801405df 100644 (file)
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -165,10 +165,19 @@ private:
     BBWorkList.push_back(BB);  // Add the block to the work list!
   }
 
-  void OperandChangedState(User *U);
+
+  // UpdateInstruction - Something changed in this instruction... Either an 
+  // operand made a transition, or the instruction is newly executable.  Change
+  // the value type of I to reflect these changes if appropriate.
+  //
   void UpdateInstruction(Instruction *I);
-};
 
+  // OperandChangedState - This method is invoked on all of the users of an
+  // instruction that was just changed state somehow....  Based on this
+  // information, we need to update the specified user of this instruction.
+  //
+  void OperandChangedState(User *U);
+};
 
 
 //===----------------------------------------------------------------------===//
@@ -259,9 +268,12 @@ bool SCCP::doSCCP() {
 
       // Hey, we just changed something!
       MadeChanges = true;
-    } else {
-      ++II;
+      continue;   // Skip the ++II at the end of the loop here...
+    } else if (Inst->isTerminator()) {
+      MadeChanges |= ConstantFoldTerminator((TerminatorInst*)Inst);
     }
+
+    ++II;
   }
 
   // Merge identical constants last: this is important because we may have just
@@ -491,7 +503,6 @@ void SCCP::OperandChangedState(User *U) {
 }
 
 
-
 // DoSparseConditionalConstantProp - Use Sparse Conditional Constant Propogation
 // to prove whether a value is constant and whether blocks are used.
 //