Revert r171427, "An intermediate step in the Attributes rewrite."

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171441 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index b847d76..a7fba3f 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -233,15 +233,8 @@
 // AttrBuilder Implementation
 //===----------------------------------------------------------------------===//
 
-void AttrBuilder::clear() {
-  AttrSet.clear();
-  Alignment = StackAlignment = Bits = 0;
-}
-
 AttrBuilder &AttrBuilder::addAttribute(Attribute::AttrKind Val){
   Bits |= AttributeImpl::getAttrMask(Val);
-
-  AttrSet.insert(Val);
   return *this;
 }
 
@@ -255,31 +248,19 @@
   assert(isPowerOf2_32(Align) && "Alignment must be a power of two.");
   assert(Align <= 0x40000000 && "Alignment too large.");
   Bits |= (Log2_32(Align) + 1) << 16;
-
-  AttrSet.insert(Attribute::Alignment);
-  Alignment = Align;
   return *this;
 }
-AttrBuilder &AttrBuilder::addStackAlignmentAttr(unsigned Align) {
+AttrBuilder &AttrBuilder::addStackAlignmentAttr(unsigned Align){
   // Default alignment, allow the target to define how to align it.
   if (Align == 0) return *this;
   assert(isPowerOf2_32(Align) && "Alignment must be a power of two.");
   assert(Align <= 0x100 && "Alignment too large.");
   Bits |= (Log2_32(Align) + 1) << 26;
-
-  AttrSet.insert(Attribute::StackAlignment);
-  StackAlignment = Align;
   return *this;
 }
 
 AttrBuilder &AttrBuilder::removeAttribute(Attribute::AttrKind Val) {
   Bits &= ~AttributeImpl::getAttrMask(Val);
-
-  AttrSet.erase(Val);
-  if (Val == Attribute::Alignment)
-    Alignment = 0;
-  else if (Val == Attribute::StackAlignment)
-    StackAlignment = 0;
   return *this;
 }