[NFC] Make getPreferredAlignment honor section markings.

This should more accurately reflect what the AsmPrinter will actually
do.

This is NFC, as far as I can tell; all the places that might be affected
already have an extra check to avoid using the result of
getPreferredAlignment in this situation.

Differential Revision: https://reviews.llvm.org/D51377

llvm-svn: 340999
diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp
index f4526c6..69d1e13 100644
--- a/llvm/lib/CodeGen/GlobalMerge.cpp
+++ b/llvm/lib/CodeGen/GlobalMerge.cpp
@@ -462,17 +462,8 @@
     for (j = i; j != -1; j = GlobalSet.find_next(j)) {
       Type *Ty = Globals[j]->getValueType();
 
-      // Make sure we use the same alignment AsmPrinter would use. There
-      // currently isn't any helper to compute that, so we compute it
-      // explicitly here.
-      //
-      // getPreferredAlignment will sometimes return an alignment higher
-      // than the explicitly specified alignment; we must ignore that
-      // if the section is explicitly specified, to avoid inserting extra
-      // padding into that section.
+      // Make sure we use the same alignment AsmPrinter would use.
       unsigned Align = DL.getPreferredAlignment(Globals[j]);
-      if (Globals[j]->hasSection() && Globals[j]->getAlignment())
-        Align = Globals[j]->getAlignment();
       unsigned Padding = alignTo(MergedSize, Align) - MergedSize;
       MergedSize += Padding;
       MergedSize += DL.getTypeAllocSize(Ty);