Scalar shifts in the OpenCL specification (as of v. 1.2) are defined to be

with respect to the lower "left-hand-side bitwidth" bits, even when negative);
see OpenCL spec 6.3j. This patch both implements this behaviour in the code
generator and "constant folding" bits of Sema, and also prevents tests
to detect undefinedness in terms of the weaker C99 or C++ specifications
from being applied. 


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171755 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index b71491008b..bac897748f 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -6578,6 +6578,11 @@ static bool isScopedEnumerationType(QualType T) {
 static void DiagnoseBadShiftValues(Sema& S, ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc, unsigned Opc,
                                    QualType LHSType) {
+  // OpenCL 6.3j: shift values are effectively % word size of LHS (more defined),
+  // so skip remaining warnings as we don't want to modify values within Sema.
+  if (S.getLangOpts().OpenCL)
+    return;
+
   llvm::APSInt Right;
   // Check right/shifter operand
   if (RHS.get()->isValueDependent() ||