commit 25b009a9d2a79929112d3c28c7dd1730bf5246c8
author Richard Smith <richard-llvm@metafoo.co.uk> Fri Dec 16 19:31:14 2011 +0000
committer Richard Smith <richard-llvm@metafoo.co.uk> Fri Dec 16 19:31:14 2011 +0000
tree dc2108ccb1983383eb86a78e2b333c41dd0eced4
parent 08d6e032a2a0a8656d12b3b7b93942987bb12eb7

PR11594: Don't blindly build a UnaryOperator UO_Minus on an expression which
might not be an rvalue when checking array accesses. Instead, pass through a
flag indicating the array index is negated.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146753 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaChecking.cpp

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index c8f2d05..9bb532b 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -4277,7 +4277,7 @@
 
 void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
                             const ArraySubscriptExpr *ASE,
-                            bool AllowOnePastEnd) {
+                            bool AllowOnePastEnd, bool IndexNegated) {
   IndexExpr = IndexExpr->IgnoreParenCasts();
   if (IndexExpr->isValueDependent())
     return;
@@ -4292,6 +4292,8 @@
   llvm::APSInt index;
   if (!IndexExpr->EvaluateAsInt(index, Context))
     return;
+  if (IndexNegated)
+    index = -index;
 
   const NamedDecl *ND = NULL;
   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))

lib/Sema/SemaExpr.cpp

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index c18d37d..552d0e7 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -6203,11 +6203,9 @@
       if (!checkArithmeticOpPointerOperand(*this, Loc, LHS.get()))
         return QualType();
 
-      Expr *IExpr = RHS.get()->IgnoreParenCasts();
-      UnaryOperator negRex(IExpr, UO_Minus, IExpr->getType(), VK_RValue,
-                           OK_Ordinary, IExpr->getExprLoc());
       // Check array bounds for pointer arithemtic
-      CheckArrayAccess(LHS.get()->IgnoreParenCasts(), &negRex);
+      CheckArrayAccess(LHS.get(), RHS.get(), /*ArraySubscriptExpr*/0,
+                       /*AllowOnePastEnd*/true, /*IndexNegated*/true);
 
       if (CompLHSTy) *CompLHSTy = LHS.get()->getType();
       return LHS.get()->getType();