[llvm] r232561 - Appease AArch64ISelLowering.cpp miscompiled by g++-4.7.2.

[NAKAMURA Takumi]

Author: chapuni
Date: Tue Mar 17 17:55:01 2015
New Revision: 232561

URL: http://llvm.org/viewvc/llvm-project?rev=232561&view=rev
Log:
Appease AArch64ISelLowering.cpp miscompiled by g++-4.7.2.

I will revert this when 4.7.3 is ready.

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp

Modified: llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp?rev=232561&r1=232560&r2=232561&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp Tue Mar 17 17:55:01 2015
@@ -7201,6 +7201,12 @@ static SDValue performConcatVectorsCombi
         (N00VT == MVT::v2i64 || N00VT == MVT::v4i32) &&
         N00VT.getScalarSizeInBits() == 4 * VT.getScalarSizeInBits()) {
       MVT MidVT = (N00VT == MVT::v2i64 ? MVT::v2i32 : MVT::v4i16);
+#if defined(__GNUC__)
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 7 && __GNUC_PATCHLEVEL__ == 2
+      // FIXME: g++-4.7.2 might miscompile PerformDAGCombine().
+      asm volatile("":::"memory");
+#endif
+#endif
       MVT ConcatMidVT = MVT::getVectorVT(MidVT.getVectorElementType(),
                                          MidVT.getVectorNumElements() * 2);
       return DAG.getNode(