[ARM64] Enable alignment control option in front-end for ARM64 - LLVM.

[kevin.qin]

Summary

This is the modification in LLVM part.

[t.p.northover]

Hi Kevin,

This should probably be tested (if you're lucky there's one hanging around in the AArch64 directory that you can just add an arm64 RUN line to).

Cheers.

Tim.

[kevin.qin]

Hi Tim,

There is already a test case in ARM64. See
'llvm/test/CodeGen/ARM64/strict-align.ll'.

2014-04-23 18:09 GMT+08:00 Tim Northover <[e-mail]>:

Hi Kevin,

This should probably be tested (if you're lucky there's one hanging around
in the AArch64 directory that you can just add an arm64 RUN line to).

Cheers.

Tim.

http://reviews.llvm.org/D3467

[kevin.qin]

Add new run line to test "-arm64-no-strict-align".

[t.p.northover]

Thanks Kevin. That looks fine now.

Tim.

lib/Target/ARM64/ARM64ISelLowering.cpp

                      cl::desc("Generate ARM64 tail calls (TEMPORARY OPTION)."),
                      cl::init(true));
 
-static cl::opt<bool>
-StrictAlign("arm64-strict-align", cl::Hidden,
-            cl::desc("Disallow all unaligned memory accesses"));
+enum AlignMode {
+  StrictAlign,
+  NoStrictAlign
+};
+
+static cl::opt<AlignMode>
+Align(cl::desc("Load/store alignment support"),
+      cl::Hidden, cl::init(NoStrictAlign),
+      cl::values(
+          clEnumValN(StrictAlign,   "arm64-strict-align",
+                     "Disallow all unaligned memory accesses"),
+          clEnumValN(NoStrictAlign, "arm64-no-strict-align",
+                     "Allow unaligned memory accesses"),
+          clEnumValEnd));
 
 // Place holder until extr generation is tested fully.
 static cl::opt<bool>

 
   setDivIsWellDefined(true);
 
-  RequireStrictAlign = StrictAlign;
+  RequireStrictAlign = (Align == StrictAlign);
 
   setHasExtractBitsInsn(true);
 

test/CodeGen/ARM64/strict-align.ll

 ; RUN: llc < %s -mtriple=arm64-apple-darwin | FileCheck %s
+; RUN: llc < %s -mtriple=arm64-apple-darwin -arm64-no-strict-align | FileCheck %s
 ; RUN: llc < %s -mtriple=arm64-apple-darwin -arm64-strict-align | FileCheck %s --check-prefix=CHECK-STRICT
 
 define i32 @f0(i32* nocapture %p) nounwind {