Fix indenting, remove tabs.

Learn from sext and zext. The destination value falls within the range of the
source type.

Generalize properties regarding constant ints.

Get smarter about marking blocks as unreachable. If 1 >= 2 in order for this
block to execute, then it isn't reachable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33889 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/PredicateSimplifier.cpp b/lib/Transforms/Scalar/PredicateSimplifier.cpp
index a11d5bd..a01ae7f 100644 (file)
--- a/lib/Transforms/Scalar/PredicateSimplifier.cpp
+++ b/lib/Transforms/Scalar/PredicateSimplifier.cpp
@@ -52,7 +52,7 @@
 // responsible for analyzing the variable and seeing what new inferences
 // can be made from each property. For example:
 //
-//   %P = setne int* %ptr, null
+//   %P = icmp ne int* %ptr, null
 //   %a = and bool %P, %Q
 //   br bool %a label %cond_true, label %cond_false
 //
@@ -140,14 +140,14 @@ namespace {
 
   static bool validPredicate(LatticeVal LV) {
     switch (LV) {
-    case GT: case GE: case LT: case LE: case NE:
-    case SGTULT: case SGT: case SGEULE:
-    case SLTUGT: case SLT: case SLEUGE:
-    case ULT: case UGT:
-    case SLE: case SGE: case ULE: case UGE:
-      return true;
-    default:
-      return false;
+      case GT: case GE: case LT: case LE: case NE:
+      case SGTULT: case SGT: case SGEULE:
+      case SLTUGT: case SLT: case SLEUGE:
+      case ULT: case UGT:
+      case SLE: case SGE: case ULE: case UGE:
+        return true;
+      default:
+        return false;
     }
   }
 
@@ -415,7 +415,7 @@ namespace {
         if (iULT == end || iUGT == end) {
           if (iULT == end) iSLT = last;  else iSLT = iULT;
           if (iUGT == end) iSGT = begin; else iSGT = iUGT;
-       } else if (iULT->first->getSExtValue() < 0) {
+        } else if (iULT->first->getSExtValue() < 0) {
           assert(iUGT->first->getSExtValue() >= 0 && "Bad sign comparison.");
           iSGT = iUGT;
           iSLT = iULT;
@@ -424,7 +424,7 @@ namespace {
                  iUGT->first->getSExtValue() < 0 && "Bad sign comparison.");
           iSGT = iULT;
           iSLT = iUGT;
-       }
+        }
 
         if (iSGT != end &&
             iSGT->first->getSExtValue() < CI->getSExtValue()) iSGT = end;
@@ -436,13 +436,13 @@ namespace {
             if (iSLT == end ||
                 begin->first->getSExtValue() > iSLT->first->getSExtValue())
               iSLT = begin;
-       }
+        }
         if (last != end) {
           if (last->first->getSExtValue() > CI->getSExtValue())
             if (iSGT == end ||
                 last->first->getSExtValue() < iSGT->first->getSExtValue())
               iSGT = last;
-       }
+        }
       }
 
       if (iULT != end) addInequality(iULT->second, index, TreeRoot, ULT);
@@ -868,7 +868,7 @@ namespace {
       if (n1) assert(V1 == IG.node(n1)->getValue() && "Value isn't canonical.");
       if (n2) assert(V2 == IG.node(n2)->getValue() && "Value isn't canonical.");
 
-      if (compare(V2, V1)) { std::swap(V1, V2); std::swap(n1, n2); }
+      assert(!compare(V2, V1) && "Please order parameters to makeEqual.");
 
       assert(!isa<Constant>(V2) && "Tried to remove a constant.");
 
@@ -1398,10 +1398,22 @@ namespace {
 
         DEBUG(IG.dump());
 
-        // TODO: actually check the constants and add to UB.
-        if (isa<Constant>(O.LHS) && isa<Constant>(O.RHS)) {
-          WorkList.pop_front();
-          continue;
+        // If they're both Constant, skip it. Check for contradiction and mark
+        // the BB as unreachable if so.
+        if (Constant *CI_L = dyn_cast<Constant>(O.LHS)) {
+          if (Constant *CI_R = dyn_cast<Constant>(O.RHS)) {
+            if (ConstantExpr::getCompare(O.Op, CI_L, CI_R) ==
+                ConstantInt::getFalse())
+              UB.mark(TopBB);
+
+            WorkList.pop_front();
+            continue;
+          }
+        }
+
+        if (compare(O.RHS, O.LHS)) {
+          std::swap(O.LHS, O.RHS);
+          O.Op = ICmpInst::getSwappedPredicate(O.Op);
         }
 
         if (O.Op == ICmpInst::ICMP_EQ) {
@@ -1416,7 +1428,7 @@ namespace {
               UB.mark(TopBB);
           } else {
             if (isRelatedBy(O.LHS, O.RHS, ICmpInst::getInversePredicate(O.Op))){
-              DOUT << "inequality contradiction!\n";
+              UB.mark(TopBB);
               WorkList.pop_front();
               continue;
             }
@@ -1438,6 +1450,31 @@ namespace {
               continue;
             }
 
+            // Generalize %x u> -10 to %x > -10.
+            if (ConstantInt *CI = dyn_cast<ConstantInt>(O.RHS)) {
+              // xform doesn't apply to i1
+              if (CI->getType()->getBitWidth() > 1) {
+                if (LV == SLT && CI->getSExtValue() < 0) {
+                  // i8 %x s< -5 implies %x < -5 and %x u> 127
+
+                  const IntegerType *Ty = CI->getType();
+                  LV = LT;
+                  add(O.LHS, ConstantInt::get(Ty, Ty->getBitMask() >> 1),
+                      ICmpInst::ICMP_UGT);
+                } else if (LV == SGT && CI->getSExtValue() >= 0) {
+                  // i8 %x s> 5 implies %x > 5 and %x u< 128
+
+                  const IntegerType *Ty = CI->getType();
+                  LV = LT;
+                  add(O.LHS, ConstantInt::get(Ty, 1 << Ty->getBitWidth()),
+                      ICmpInst::ICMP_ULT);
+                } else if (CI->getSExtValue() >= 0) {
+                  if (LV == ULT || LV == SLT) LV = LT;
+                  if (LV == UGT || LV == SGT) LV = GT;
+                }
+              }
+            }
+
             IG.addInequality(n1, n2, Top, LV);
 
             if (Instruction *I1 = dyn_cast<Instruction>(O.LHS)) {
@@ -1531,6 +1568,9 @@ namespace {
       void visitLoadInst(LoadInst &LI);
       void visitStoreInst(StoreInst &SI);
 
+      void visitSExtInst(SExtInst &SI);
+      void visitZExtInst(ZExtInst &ZI);
+
       void visitBinaryOperator(BinaryOperator &BO);
     };
 
@@ -1730,23 +1770,41 @@ namespace {
     VRP.solve();
   }
 
+  void PredicateSimplifier::Forwards::visitSExtInst(SExtInst &SI) {
+    VRPSolver VRP(IG, UB, PS->Forest, PS->modified, &SI);
+    const IntegerType *Ty = cast<IntegerType>(SI.getSrcTy());
+    VRP.add(ConstantInt::get(SI.getDestTy(), ~(Ty->getBitMask() >> 1)),
+            &SI, ICmpInst::ICMP_SLE);
+    VRP.add(ConstantInt::get(SI.getDestTy(), (1 << (Ty->getBitWidth()-1)) - 1),
+            &SI, ICmpInst::ICMP_SGE);
+    VRP.solve();
+  }
+
+  void PredicateSimplifier::Forwards::visitZExtInst(ZExtInst &ZI) {
+    VRPSolver VRP(IG, UB, PS->Forest, PS->modified, &ZI);
+    const IntegerType *Ty = cast<IntegerType>(ZI.getSrcTy());
+    VRP.add(ConstantInt::get(ZI.getDestTy(), Ty->getBitMask()),
+            &ZI, ICmpInst::ICMP_UGE);
+    VRP.solve();
+  }
+
   void PredicateSimplifier::Forwards::visitBinaryOperator(BinaryOperator &BO) {
     Instruction::BinaryOps ops = BO.getOpcode();
 
     switch (ops) {
-    case Instruction::URem:
-    case Instruction::SRem:
-    case Instruction::UDiv:
-    case Instruction::SDiv: {
-      Value *Divisor = BO.getOperand(1);
-      VRPSolver VRP(IG, UB, PS->Forest, PS->modified, &BO);
-      VRP.add(Constant::getNullValue(Divisor->getType()), Divisor,
-              ICmpInst::ICMP_NE);
-      VRP.solve();
-      break;
-    }
-    default:
-      break;
+      case Instruction::URem:
+      case Instruction::SRem:
+      case Instruction::UDiv:
+      case Instruction::SDiv: {
+        Value *Divisor = BO.getOperand(1);
+        VRPSolver VRP(IG, UB, PS->Forest, PS->modified, &BO);
+        VRP.add(Constant::getNullValue(Divisor->getType()), Divisor,
+                ICmpInst::ICMP_NE);
+        VRP.solve();
+        break;
+      }
+      default:
+        break;
     }
   }