[llvm] 4ea6891 - [ConstraintElimination] Remove unneeded StackEntry::Condition (NFC).

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2022-06-21T15:57:29+02:00
New Revision: 4ea6891f95a878af869e01425a69099a5e48e4c6

URL: https://github.com/llvm/llvm-project/commit/4ea6891f95a878af869e01425a69099a5e48e4c6
DIFF: https://github.com/llvm/llvm-project/commit/4ea6891f95a878af869e01425a69099a5e48e4c6.diff

LOG: [ConstraintElimination] Remove unneeded StackEntry::Condition (NFC).

The field was only used for debug printing. Print constraint from the
system instead.

Added: 
    

Modified: 
    llvm/include/llvm/Analysis/ConstraintSystem.h
    llvm/lib/Transforms/Scalar/ConstraintElimination.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Analysis/ConstraintSystem.h b/llvm/include/llvm/Analysis/ConstraintSystem.h
index eab35b7a5923e..2c83658b81dcc 100644
--- a/llvm/include/llvm/Analysis/ConstraintSystem.h
+++ b/llvm/include/llvm/Analysis/ConstraintSystem.h
@@ -79,6 +79,7 @@ class ConstraintSystem {
 
   bool isConditionImplied(SmallVector<int64_t, 8> R) const;
 
+  ArrayRef<int64_t> getLastConstraint() { return Constraints[0]; }
   void popLastConstraint() { Constraints.pop_back(); }
   void popLastNVariables(unsigned N) {
     for (auto &C : Constraints) {

diff  --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 9a574fa1eb24b..31c55b5244c99 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -52,17 +52,16 @@ class ConstraintInfo;
 struct StackEntry {
   unsigned NumIn;
   unsigned NumOut;
-  Instruction *Condition;
   bool IsNot;
   bool IsSigned = false;
   /// Variables that can be removed from the system once the stack entry gets
   /// removed.
   SmallVector<Value *, 2> ValuesToRelease;
 
-  StackEntry(unsigned NumIn, unsigned NumOut, CmpInst *Condition, bool IsNot,
-             bool IsSigned, SmallVector<Value *, 2> ValuesToRelease)
-      : NumIn(NumIn), NumOut(NumOut), Condition(Condition), IsNot(IsNot),
-        IsSigned(IsSigned), ValuesToRelease(ValuesToRelease) {}
+  StackEntry(unsigned NumIn, unsigned NumOut, bool IsNot, bool IsSigned,
+             SmallVector<Value *, 2> ValuesToRelease)
+      : NumIn(NumIn), NumOut(NumOut), IsNot(IsNot), IsSigned(IsSigned),
+        ValuesToRelease(ValuesToRelease) {}
 };
 
 /// Struct to express a pre-condition of the form %Op0 Pred %Op1.
@@ -435,16 +434,21 @@ struct State {
 } // namespace
 
 #ifndef NDEBUG
-static void dumpWithNames(ConstraintTy &C,
+static void dumpWithNames(const ConstraintSystem &CS,
                           DenseMap<Value *, unsigned> &Value2Index) {
   SmallVector<std::string> Names(Value2Index.size(), "");
   for (auto &KV : Value2Index) {
     Names[KV.second - 1] = std::string("%") + KV.first->getName().str();
   }
-  ConstraintSystem CS;
-  CS.addVariableRowFill(C.Coefficients);
   CS.dump(Names);
 }
+
+static void dumpWithNames(ArrayRef<int64_t> C,
+                          DenseMap<Value *, unsigned> &Value2Index) {
+  ConstraintSystem CS;
+  CS.addVariableRowFill(C);
+  dumpWithNames(CS, Value2Index);
+}
 #endif
 
 void State::addInfoFor(BasicBlock &BB) {
@@ -553,10 +557,10 @@ void ConstraintInfo::addFact(CmpInst *Condition, bool IsNegated, unsigned NumIn,
 
     LLVM_DEBUG({
       dbgs() << "  constraint: ";
-      dumpWithNames(R, getValue2Index(R.IsSigned));
+      dumpWithNames(R.Coefficients, getValue2Index(R.IsSigned));
     });
 
-    DFSInStack.emplace_back(NumIn, NumOut, Condition, IsNegated, R.IsSigned,
+    DFSInStack.emplace_back(NumIn, NumOut, IsNegated, R.IsSigned,
                             ValuesToRelease);
 
     if (R.IsEq) {
@@ -565,7 +569,7 @@ void ConstraintInfo::addFact(CmpInst *Condition, bool IsNegated, unsigned NumIn,
         Coeff *= -1;
       CSToUse.addVariableRowFill(R.Coefficients);
 
-      DFSInStack.emplace_back(NumIn, NumOut, Condition, IsNegated, R.IsSigned,
+      DFSInStack.emplace_back(NumIn, NumOut, IsNegated, R.IsSigned,
                               SmallVector<Value *, 2>());
     }
   }
@@ -657,8 +661,13 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT) {
       assert(E.NumIn <= CB.NumIn);
       if (CB.NumOut <= E.NumOut)
         break;
-      LLVM_DEBUG(dbgs() << "Removing " << *E.Condition << " " << E.IsNot
-                        << "\n");
+      LLVM_DEBUG({
+        dbgs() << "Removing ";
+        dumpWithNames(Info.getCS(E.IsSigned).getLastConstraint(),
+                      Info.getValue2Index(E.IsSigned));
+        dbgs() << "\n";
+      });
+
       Info.popLastConstraint(E.IsSigned);
       // Remove variables in the system that went out of scope.
       auto &Mapping = Info.getValue2Index(E.IsSigned);
@@ -700,11 +709,10 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT) {
           if (!DebugCounter::shouldExecute(EliminatedCounter))
             continue;
 
-          LLVM_DEBUG(dbgs() << "Condition " << *Cmp
-                            << " implied by dominating constraints\n");
           LLVM_DEBUG({
-            for (auto &E : reverse(DFSInStack))
-              dbgs() << "   C " << *E.Condition << " " << E.IsNot << "\n";
+            dbgs() << "Condition " << *Cmp
+                   << " implied by dominating constraints\n";
+            dumpWithNames(CSToUse, Info.getValue2Index(R.IsSigned));
           });
           Cmp->replaceUsesWithIf(
               ConstantInt::getTrue(F.getParent()->getContext()), [](Use &U) {
@@ -721,11 +729,10 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT) {
           if (!DebugCounter::shouldExecute(EliminatedCounter))
             continue;
 
-          LLVM_DEBUG(dbgs() << "Condition !" << *Cmp
-                            << " implied by dominating constraints\n");
           LLVM_DEBUG({
-            for (auto &E : reverse(DFSInStack))
-              dbgs() << "   C " << *E.Condition << " " << E.IsNot << "\n";
+            dbgs() << "Condition !" << *Cmp
+                   << " implied by dominating constraints\n";
+            dumpWithNames(CSToUse, Info.getValue2Index(R.IsSigned));
           });
           Cmp->replaceAllUsesWith(
               ConstantInt::getFalse(F.getParent()->getContext()));