[llvm] r278884 - IPO: Swap || operands to avoid dereferencing end()

[Duncan P. N. Exon Smith via llvm-commits]

Author: dexonsmith
Date: Tue Aug 16 20:23:58 2016
New Revision: 278884

URL: http://llvm.org/viewvc/llvm-project?rev=278884&view=rev
Log:
IPO: Swap || operands to avoid dereferencing end()

IsOperandBundleUse conveniently indicates  whether
std::next(F->arg_begin(),UseIndex) will get to (or past) end().  Check
it first to avoid dereferencing end().

Modified:
    llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp

Modified: llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp?rev=278884&r1=278883&r2=278884&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp Tue Aug 16 20:23:58 2016
@@ -448,8 +448,8 @@ determinePointerReadAttrs(Argument *A,
       // to a operand bundle use, these cannot participate in the optimistic SCC
       // analysis.  Instead, we model the operand bundle uses as arguments in
       // call to a function external to the SCC.
-      if (!SCCNodes.count(&*std::next(F->arg_begin(), UseIndex)) ||
-          IsOperandBundleUse) {
+      if (IsOperandBundleUse ||
+          !SCCNodes.count(&*std::next(F->arg_begin(), UseIndex))) {
 
         // The accessors used on CallSite here do the right thing for calls and
         // invokes with operand bundles.