[llvm] r289826 - Fix ubsan failures in lane mask shifts

[Krzysztof Parzyszek via llvm-commits]

Author: kparzysz
Date: Thu Dec 15 10:08:49 2016
New Revision: 289826

URL: http://llvm.org/viewvc/llvm-project?rev=289826&view=rev
Log:
Fix ubsan failures in lane mask shifts

Modified:
    llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp

Modified: llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp?rev=289826&r1=289825&r2=289826&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp Thu Dec 15 10:08:49 2016
@@ -778,8 +778,10 @@ RegisterInfoEmitter::emitComposeSubRegIn
         "  LaneBitmask Result;\n"
         "  for (const MaskRolOp *Ops = CompositeSequences[IdxA]; !Ops->Mask.none(); ++Ops) {\n"
         "    LaneBitmask::Type M = LaneMask.getAsInteger() & Ops->Mask.getAsInteger();\n"
-        "    unsigned S = Ops->RotateLeft;\n"
-        "    Result |= LaneBitmask((M << S) | (M >> (LaneBitmask::BitWidth - S)));\n"
+        "    if (unsigned S = Ops->RotateLeft)\n"
+        "      Result |= LaneBitmask((M << S) | (M >> (LaneBitmask::BitWidth - S)));\n"
+        "    else\n"
+        "      Result |= LaneBitmask(M);\n"
         "  }\n"
         "  return Result;\n"
         "}\n\n";
@@ -793,8 +795,10 @@ RegisterInfoEmitter::emitComposeSubRegIn
         "  LaneBitmask Result;\n"
         "  for (const MaskRolOp *Ops = CompositeSequences[IdxA]; !Ops->Mask.none(); ++Ops) {\n"
         "    LaneBitmask::Type M = LaneMask.getAsInteger();\n"
-        "    unsigned S = Ops->RotateLeft;\n"
-        "    Result |= LaneBitmask((M >> S) | (M << (LaneBitmask::BitWidth - S)));\n"
+        "    if (unsigned S = Ops->RotateLeft)\n"
+        "      Result |= LaneBitmask((M >> S) | (M << (LaneBitmask::BitWidth - S)));\n"
+        "    else\n"
+        "      Result |= LaneBitmask(M);\n"
         "  }\n"
         "  return Result;\n"
         "}\n\n";