[cfe-commits] r64296 - /cfe/trunk/lib/CodeGen/CGExprScalar.cpp

[Chris Lattner]

Author: lattner
Date: Wed Feb 11 01:40:06 2009
New Revision: 64296

URL: http://llvm.org/viewvc/llvm-project?rev=64296&view=rev
Log:
Fix rdar://6518463, increment of a bool is always true, due to
subtle and non-obvious promotion rules.  We already handle += 
and +1 correctly.

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=64296&r1=64295&r2=64296&view=diff

==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprScalar.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp Wed Feb 11 01:40:06 2009
@@ -619,6 +619,13 @@
     // FIXME: This isn't right for VLAs.
     NextVal = llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal);
     NextVal = Builder.CreateGEP(InVal, NextVal, "ptrincdec");
+  } else if (InVal->getType() == llvm::Type::Int1Ty && isInc) {
+    // Bool++ is an interesting case, due to promotion rules, we get:
+    // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 ->
+    // Bool = ((int)Bool+1) != 0
+    // An interesting aspect of this is that increment is always true.
+    // Decrement does not have this property.
+    NextVal = llvm::ConstantInt::getTrue();
   } else {
     // Add the inc/dec to the real part.
     if (isa<llvm::IntegerType>(InVal->getType()))