[Alignment][NFC] Use Align for TargetFrameLowering/Subtarget

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68993

llvm-svn: 375084
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
index f5848aa..936feb0 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
@@ -866,9 +866,7 @@
   // on the pointer value itself may rely on the alignment / known low bits of
   // the pointer. Set this to something above the minimum to avoid needing
   // dynamic realignment in common cases.
-  unsigned getStackAlignment() const {
-    return 16;
-  }
+  Align getStackAlignment() const { return Align(16); }
 
   bool enableMachineScheduler() const override {
     return true;
@@ -1257,9 +1255,7 @@
     return Gen;
   }
 
-  unsigned getStackAlignment() const {
-    return 4;
-  }
+  Align getStackAlignment() const { return Align(4); }
 
   R600Subtarget &initializeSubtargetDependencies(const Triple &TT,
                                                  StringRef GPU, StringRef FS);