[cfe-commits] r78765 - /cfe/trunk/lib/CodeGen/CGExprScalar.cpp

[Dan Gohman]

Author: djg
Date: Tue Aug 11 20:16:29 2009
New Revision: 78765

URL: http://llvm.org/viewvc/llvm-project?rev=78765&view=rev
Log:
Use the new nsw form of add for signed integer addition.

Modified:
    cfe/trunk/lib/CodeGen/CGExprScalar.cpp

Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprScalar.cpp?rev=78765&r1=78764&r2=78765&view=diff

==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprScalar.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp Tue Aug 11 20:16:29 2009
@@ -741,7 +741,12 @@
     NextVal = llvm::ConstantInt::getTrue(VMContext);
   } else if (isa<llvm::IntegerType>(InVal->getType())) {
     NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
-    NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
+
+    // Signed integer overflow is undefined behavior.
+    if (ValTy->isSignedIntegerType())
+      NextVal = Builder.CreateNSWAdd(InVal, NextVal, isInc ? "inc" : "dec");
+    else
+      NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
   } else {
     // Add the inc/dec to the real part.
     if (InVal->getType() == llvm::Type::FloatTy)
@@ -1033,7 +1038,11 @@
     
     if (Ops.LHS->getType()->isFPOrFPVector())
       return Builder.CreateFAdd(Ops.LHS, Ops.RHS, "add");
-      
+
+    // Signed integer overflow is undefined behavior.
+    if (Ops.Ty->isSignedIntegerType())
+      return Builder.CreateNSWAdd(Ops.LHS, Ops.RHS, "add");
+
     return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add");
   }