Add a per target max vector alignment field (e.g., 32-byte alignment for x86 due to
AVX).  Currently, if no aligned attribute is specified the alignment of a vector is
inferred from its size.  Thus, very large vectors will be over-aligned with no 
benefit.  Target owners should set this target max.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160209 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/vector-alignment.c b/test/CodeGen/vector-alignment.c
new file mode 100644
index 0000000..92d1ae7
--- /dev/null
+++ b/test/CodeGen/vector-alignment.c
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -w -triple x86_64-apple-darwin10 -emit-llvm -o - %s | FileCheck %s
+// rdar://11759609
+
+// At or below target max alignment with no aligned attribute should align based
+// on the size of vector.
+double __attribute__((vector_size(16))) v1;
+// CHECK: @v1 {{.*}}, align 16
+double __attribute__((vector_size(32))) v2;
+// CHECK: @v2 {{.*}}, align 32
+
+// Alignment above target max alignment with no aligned attribute should align
+// based on the target max.
+double __attribute__((vector_size(64))) v3;
+// CHECK: @v3 {{.*}}, align 32
+double __attribute__((vector_size(1024))) v4;
+// CHECK: @v4 {{.*}}, align 32
+
+// Aliged attribute should always override.
+double __attribute__((vector_size(16), aligned(16))) v5;
+// CHECK: @v5 {{.*}}, align 16
+double __attribute__((vector_size(16), aligned(64))) v6;
+// CHECK: @v6 {{.*}}, align 64
+double __attribute__((vector_size(32), aligned(16))) v7;
+// CHECK: @v7 {{.*}}, align 16
+double __attribute__((vector_size(32), aligned(64))) v8;
+// CHECK: @v8 {{.*}}, align 64
+
+// Check non-power of 2 widths.
+double __attribute__((vector_size(24))) v9;
+// CHECK: @v9 {{.*}}, align 32
+double __attribute__((vector_size(40))) v10;
+// CHECK: @v10 {{.*}}, align 32
+
+// Check non-power of 2 widths with aligned attribute.
+double __attribute__((vector_size(24), aligned(64))) v11;
+// CHECK: @v11 {{.*}}, align 64
+double __attribute__((vector_size(80), aligned(16))) v12;
+// CHECK: @v12 {{.*}}, align 16