[NFC] Change MemIntrinsicInst::setAlignment() to take an unsigned instead of a Constant

Summary:
 In preparation for https://reviews.llvm.org/D41675 this NFC changes this
prototype of MemIntrinsicInst::setAlignment() to accept an unsigned instead
of a Constant.

llvm-svn: 322403
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 40e52ee..31dea89 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -190,7 +190,7 @@
   unsigned CopyAlign = MI->getAlignment();
 
   if (CopyAlign < MinAlign) {
-    MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), MinAlign, false));
+    MI->setAlignment(MinAlign);
     return MI;
   }
 
@@ -265,8 +265,7 @@
 Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) {
   unsigned Alignment = getKnownAlignment(MI->getDest(), DL, MI, &AC, &DT);
   if (MI->getAlignment() < Alignment) {
-    MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
-                                             Alignment, false));
+    MI->setAlignment(Alignment);
     return MI;
   }