[Hexagon] Specify vector alignment in DataLayout string

The DataLayout can calculate alignment of vectors based on the alignment
of the element type and the number of elements. In fact, it is the product
of these two values. The problem is that for vectors of N x i1, this will
return the alignment of N bytes, since the alignment of i1 is 8 bits. The
vector types of vNi1 should be aligned to N bits instead. Provide explicit
alignment for HVX vectors to avoid such complications.

llvm-svn: 260678
diff --git a/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
index 34b03fb..4d7a1f4 100644
--- a/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
@@ -121,19 +121,19 @@
   FunctionPass *createHexagonStoreWidening();
 } // end namespace llvm;
 
-/// HexagonTargetMachine ctor - Create an ILP32 architecture model.
-///
 
-/// Hexagon_TODO: Do I need an aggregate alignment?
-///
 HexagonTargetMachine::HexagonTargetMachine(const Target &T, const Triple &TT,
                                            StringRef CPU, StringRef FS,
                                            const TargetOptions &Options,
                                            Reloc::Model RM, CodeModel::Model CM,
                                            CodeGenOpt::Level OL)
-    : LLVMTargetMachine(T, "e-m:e-p:32:32:32-i64:64:64-i32:32:32-i16:16:16-"
-                        "i1:8:8-f64:64:64-f32:32:32-v64:64:64-v32:32:32-a:0-"
-                        "n16:32", TT, CPU, FS, Options, RM, CM, OL),
+    // Specify the vector alignment explicitly. For v512x1, the calculated
+    // alignment would be 512*alignment(i1), which is 512 bytes, instead of
+    // the required minimum of 64 bytes.
+    : LLVMTargetMachine(T, "e-m:e-p:32:32:32-a:0-n16:32-"
+         "i64:64:64-i32:32:32-i16:16:16-i1:8:8-f32:32:32-f64:64:64-"
+         "v32:32:32-v64:64:64-v512:512:512-v1024:1024:1024-v2048:2048:2048",
+         TT, CPU, FS, Options, RM, CM, OL),
       TLOF(make_unique<HexagonTargetObjectFile>()) {
   initAsmInfo();
 }