From 6bbe671e1c58dd58fcf0165c1127dda5037ad3e2 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 28 Jul 2010 20:56:48 +0000
Subject: [PATCH] Make GlobalValue alignment consistent with load, store, and
 alloca alignment, fixing silent truncation of alignment values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109653 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/GlobalValue.h   | 7 +++----
 lib/VMCore/Globals.cpp       | 9 ++++++++-
 test/Assembler/align-inst.ll | 2 ++
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/llvm/GlobalValue.h b/include/llvm/GlobalValue.h
index d175080a667..f4bee85b45f 100644
--- a/include/llvm/GlobalValue.h
+++ b/include/llvm/GlobalValue.h
@@ -74,11 +74,10 @@ public:
     removeDeadConstantUsers();   // remove any dead constants using this.
   }
 
-  unsigned getAlignment() const { return Alignment; }
-  void setAlignment(unsigned Align) {
-    assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
-    Alignment = Align;
+  unsigned getAlignment() const {
+    return (1u << Alignment) >> 1;
   }
+  void setAlignment(unsigned Align);
 
   VisibilityTypes getVisibility() const { return VisibilityTypes(Visibility); }
   bool hasDefaultVisibility() const { return Visibility == DefaultVisibility; }
diff --git a/lib/VMCore/Globals.cpp b/lib/VMCore/Globals.cpp
index b758eb8702a..96716eeb349 100644
--- a/lib/VMCore/Globals.cpp
+++ b/lib/VMCore/Globals.cpp
@@ -102,7 +102,14 @@ void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
   setVisibility(Src->getVisibility());
 }
 
-
+void GlobalValue::setAlignment(unsigned Align) {
+  assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
+  assert(Align <= MaximumAlignment &&
+         "Alignment is greater than MaximumAlignment!");
+  Alignment = Log2_32(Align) + 1;
+  assert(getAlignment() == Align && "Alignment representation error!");
+}
+  
 //===----------------------------------------------------------------------===//
 // GlobalVariable Implementation
 //===----------------------------------------------------------------------===//
diff --git a/test/Assembler/align-inst.ll b/test/Assembler/align-inst.ll
index 7bf0b6493b6..6f7100e065d 100644
--- a/test/Assembler/align-inst.ll
+++ b/test/Assembler/align-inst.ll
@@ -1,5 +1,7 @@
 ; RUN: llvm-as %s -o /dev/null
 
+@A = global i1 0, align 536870912
+
 define void @foo() {
   %p = alloca i1, align 536870912
   load i1* %p, align 536870912