Add llvm patch corresponding to r289072.

contrib/llvm/patches/patch-07-undo-llvm-r240144-iostream-sigbus.diff

@@ -0,0 +1,50 @@
+Temporarily revert upstream llvm trunk r240144 (by Michael Zolotukhin):
+
+  [SLP] Vectorize for all-constant entries.
+
+This should fix libc++'s iostream initialization SIGBUSing whenever the
+global cout symbol is not aligned to 16 bytes.
+
+Introduced here: http://svnweb.freebsd.org/changeset/base/289072
+
+Index: lib/Transforms/Vectorize/SLPVectorizer.cpp
+===================================================================
+--- lib/Transforms/Vectorize/SLPVectorizer.cpp
++++ lib/Transforms/Vectorize/SLPVectorizer.cpp
+@@ -1642,10 +1642,8 @@ bool BoUpSLP::isFullyVectorizableTinyTree() {
+   if (VectorizableTree.size() != 2)
+     return false;
+ 
+-  // Handle splat and all-constants stores.
+-  if (!VectorizableTree[0].NeedToGather &&
+-      (allConstant(VectorizableTree[1].Scalars) ||
+-       isSplat(VectorizableTree[1].Scalars)))
++  // Handle splat stores.
++  if (!VectorizableTree[0].NeedToGather && isSplat(VectorizableTree[1].Scalars))
+     return true;
+ 
+   // Gathering cost would be too much for tiny trees.
+Index: test/Transforms/SLPVectorizer/X86/tiny-tree.ll
+===================================================================
+--- test/Transforms/SLPVectorizer/X86/tiny-tree.ll
++++ test/Transforms/SLPVectorizer/X86/tiny-tree.ll
+@@ -153,19 +153,3 @@ define void @store_splat(float*, float) {
+   store float %1, float* %6, align 4
+   ret void
+ }
+-
+-
+-; CHECK-LABEL: store_const
+-; CHECK: store <4 x i32>
+-define void @store_const(i32* %a) {
+-entry:
+-  %ptr0 = getelementptr inbounds i32, i32* %a, i64 0
+-  store i32 10, i32* %ptr0, align 4
+-  %ptr1 = getelementptr inbounds i32, i32* %a, i64 1
+-  store i32 30, i32* %ptr1, align 4
+-  %ptr2 = getelementptr inbounds i32, i32* %a, i64 2
+-  store i32 20, i32* %ptr2, align 4
+-  %ptr3 = getelementptr inbounds i32, i32* %a, i64 3
+-  store i32 40, i32* %ptr3, align 4
+-  ret void
+-}