Appease AArch64ISelLowering.cpp miscompiled by g++-4.7.2.

I will revert this when 4.7.3 is ready.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232561 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp
index f1073beb32f32576d1a63cf5886466f2a24b0c39..464f56780dfd1a74c24704a7aafe53cb81a2a806 100644 (file)
--- a/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -7201,6 +7201,12 @@ static SDValue performConcatVectorsCombine(SDNode *N,
         (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(