Fix comment to reflect code, and remove an unused argument

[oota-llvm.git] / lib / Analysis / LazyValueInfo.cpp

diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp
index 7ec35cdcc5bdb11c805d47dd8125b00e26f6eb1f..d3a437f9405057ea4b8af7545c86756fd533f30e 100644 (file)
--- a/lib/Analysis/LazyValueInfo.cpp
+++ b/lib/Analysis/LazyValueInfo.cpp
@@ -91,6 +91,11 @@ public:
       Res.markNotConstant(C);
     return Res;
   }
+  static LVILatticeVal getRange(ConstantRange CR) {
+    LVILatticeVal Res;
+    Res.markConstantRange(CR);
+    return Res;
+  }
   
   bool isUndefined() const     { return Tag == undefined; }
   bool isConstant() const      { return Tag == constant; }
@@ -379,7 +384,6 @@ namespace {
 } // end anonymous namespace
 
 void LazyValueInfoCache::LVIValueHandle::deleted() {
-  Parent->ValueCache.erase(*this);
   for (std::set<std::pair<BasicBlock*, Value*> >::iterator
        I = Parent->OverDefinedCache.begin(),
        E = Parent->OverDefinedCache.end();
@@ -389,6 +393,10 @@ void LazyValueInfoCache::LVIValueHandle::deleted() {
     if (tmp->second == getValPtr())
       Parent->OverDefinedCache.erase(tmp);
   }
+  
+  // This erasure deallocates *this, so it MUST happen after we're done
+  // using any and all members of *this.
+  Parent->ValueCache.erase(*this);
 }
 
 
@@ -506,15 +514,38 @@ LVILatticeVal LVIQuery::getEdgeValue(BasicBlock *BBFrom, BasicBlock *BBTo) {
       
       // If the condition of the branch is an equality comparison, we may be
       // able to infer the value.
-      if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition()))
-        if (ICI->isEquality() && ICI->getOperand(0) == Val &&
-            isa<Constant>(ICI->getOperand(1))) {
+      ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition());
+      if (ICI && ICI->getOperand(0) == Val &&
+          isa<Constant>(ICI->getOperand(1))) {
+        if (ICI->isEquality()) {
           // We know that V has the RHS constant if this is a true SETEQ or
           // false SETNE. 
           if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
             return LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
           return LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
         }
+          
+        if (ConstantInt *CI = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
+          // Calculate the range of values that would satisfy the comparison.
+          ConstantRange CmpRange(CI->getValue(), CI->getValue()+1);
+          ConstantRange TrueValues =
+            ConstantRange::makeICmpRegion(ICI->getPredicate(), CmpRange);
+            
+          // If we're interested in the false dest, invert the condition.
+          if (!isTrueDest) TrueValues = TrueValues.inverse();
+          
+          // Figure out the possible values of the query BEFORE this branch.  
+          LVILatticeVal InBlock = getBlockValue(BBFrom);
+          if (!InBlock.isConstantRange()) return InBlock;
+            
+          // Find all potential values that satisfy both the input and output
+          // conditions.
+          ConstantRange PossibleValues =
+            TrueValues.intersectWith(InBlock.getConstantRange());
+            
+          return LVILatticeVal::getRange(PossibleValues);
+        }
+      }
     }
   }
 
@@ -730,7 +761,7 @@ LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
     ConstantRange TrueValues = ConstantRange::makeICmpRegion(Pred, RHS);
     if (CR.intersectWith(TrueValues).isEmptySet())
       return False;
-    else if (CR.intersectWith(TrueValues) == CR)
+    else if (TrueValues.contains(CR))
       return True;
     
     return Unknown;