commit c2c90011a688c04a4e980282f08c267e081c4b00
author Chris Lattner <sabre@nondot.org> Sun Feb 27 23:02:32 2011 +0000
committer Chris Lattner <sabre@nondot.org> Sun Feb 27 23:02:32 2011 +0000
tree f543ec6056c1b38c7b6bc1ae2fb4b4b1090734e1
parent a02411e4d58b1730bea2a990822858ecc31e8eb1

Change the interface to ConstantFoldsToSimpleInteger to not encode 
a bool + success into one tri-state integer, simplifying things.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126592 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CodeGenFunction.cpp

diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index f1b7286..ca47870 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -408,22 +408,23 @@
 }
 
 
-/// ConstantFoldsToSimpleInteger - If the sepcified expression does not fold to
-/// a constant, or if it does but contains a label, return 0.  If it constant
-/// folds to 'true' and does not contain a label, return 1, if it constant folds
-/// to 'false' and does not contain a label, return -1.
-int CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond) {
+/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
+/// to a constant, or if it does but contains a label, return false.  If it
+/// constant folds return true and set the boolean result in Result.
+bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
+                                                   bool &ResultBool) {
   // FIXME: Rename and handle conversion of other evaluatable things
   // to bool.
   Expr::EvalResult Result;
   if (!Cond->Evaluate(Result, getContext()) || !Result.Val.isInt() ||
       Result.HasSideEffects)
-    return 0;  // Not foldable, not integer or not fully evaluatable.
+    return false;  // Not foldable, not integer or not fully evaluatable.
 
   if (CodeGenFunction::ContainsLabel(Cond))
-    return 0;  // Contains a label.
+    return false;  // Contains a label.
 
-  return Result.Val.getInt().getBoolValue() ? 1 : -1;
+  ResultBool = Result.Val.getInt().getBoolValue();
+  return true;
 }
 
 
@@ -442,14 +443,17 @@
     if (CondBOp->getOpcode() == BO_LAnd) {
       // If we have "1 && X", simplify the code.  "0 && X" would have constant
       // folded if the case was simple enough.
-      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS()) == 1) {
+      bool ConstantBool;
+      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
+          ConstantBool) {
         // br(1 && X) -> br(X).
         return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
       }
 
       // If we have "X && 1", simplify the code to use an uncond branch.
       // "X && 0" would have been constant folded to 0.
-      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS()) == 1) {
+      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
+          ConstantBool) {
         // br(X && 1) -> br(X).
         return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
       }
@@ -468,17 +472,22 @@
       eval.end(*this);
 
       return;
-    } else if (CondBOp->getOpcode() == BO_LOr) {
+    }
+    
+    if (CondBOp->getOpcode() == BO_LOr) {
       // If we have "0 || X", simplify the code.  "1 || X" would have constant
       // folded if the case was simple enough.
-      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS()) == -1) {
+      bool ConstantBool;
+      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
+          !ConstantBool) {
         // br(0 || X) -> br(X).
         return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
       }
 
       // If we have "X || 0", simplify the code to use an uncond branch.
       // "X || 1" would have been constant folded to 1.
-      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS()) == -1) {
+      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
+          !ConstantBool) {
         // br(X || 0) -> br(X).
         return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
       }