[Alignment][NFC] migrate DataLayout::getPreferredAlignment

This 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

Differential Revision: https://reviews.llvm.org/D82752

1 files changed, 14 insertions, 21 deletions

diff --git a/llvm/lib/IR/DataLayout.cpp b/llvm/lib/IR/DataLayout.cpp
index 58ef87a..b0613c8 100644
--- a/llvm/lib/IR/DataLayout.cpp
+++ b/llvm/lib/IR/DataLayout.cpp
@@ -846,15 +846,14 @@ int64_t DataLayout::getIndexedOffsetInType(Type *ElemTy,
   return Result;
 }
 
-/// getPreferredAlignment - Return the preferred alignment of the specified
-/// global.  This includes an explicitly requested alignment (if the global
-/// has one).
-unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const {
-  unsigned GVAlignment = GV->getAlignment();
+/// getPreferredAlign - Return the preferred alignment of the specified global.
+/// This includes an explicitly requested alignment (if the global has one).
+Align DataLayout::getPreferredAlign(const GlobalVariable *GV) const {
+  MaybeAlign GVAlignment = GV->getAlign();
   // If a section is specified, always precisely honor explicit alignment,
   // so we don't insert padding into a section we don't control.
   if (GVAlignment && GV->hasSection())
-    return GVAlignment;
+    return *GVAlignment;
 
   // If no explicit alignment is specified, compute the alignment based on
   // the IR type. If an alignment is specified, increase it to match the ABI
@@ -863,30 +862,24 @@ unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const {
   // FIXME: Not sure it makes sense to use the alignment of the type if
   // there's already an explicit alignment specification.
   Type *ElemType = GV->getValueType();
-  unsigned Alignment = getPrefTypeAlignment(ElemType);
-  if (GVAlignment >= Alignment) {
-    Alignment = GVAlignment;
-  } else if (GVAlignment != 0) {
-    Alignment = std::max(GVAlignment, getABITypeAlignment(ElemType));
+  Align Alignment = getPrefTypeAlign(ElemType);
+  if (GVAlignment) {
+    if (*GVAlignment >= Alignment)
+      Alignment = *GVAlignment;
+    else
+      Alignment = std::max(*GVAlignment, getABITypeAlign(ElemType));
   }
 
   // If no explicit alignment is specified, and the global is large, increase
   // the alignment to 16.
   // FIXME: Why 16, specifically?
-  if (GV->hasInitializer() && GVAlignment == 0) {
-    if (Alignment < 16) {
+  if (GV->hasInitializer() && !GVAlignment) {
+    if (Alignment < Align(16)) {
       // If the global is not external, see if it is large.  If so, give it a
       // larger alignment.
       if (getTypeSizeInBits(ElemType) > 128)
-        Alignment = 16;    // 16-byte alignment.
+        Alignment = Align(16); // 16-byte alignment.
     }
   }
   return Alignment;
 }
-
-/// getPreferredAlignmentLog - Return the preferred alignment of the
-/// specified global, returned in log form.  This includes an explicitly
-/// requested alignment (if the global has one).
-unsigned DataLayout::getPreferredAlignmentLog(const GlobalVariable *GV) const {
-  return Log2_32(getPreferredAlignment(GV));
-}