From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Tue, 22 Dec 2015 19:50:22 +0000 (+0000)
Subject: Delete dead GlobalAliases.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=937ba4cad8c9d5c8d5d2de06e535299a85ff42c6;p=oota-llvm.git

Delete dead GlobalAliases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256276 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 06a319017ee..2873ee72169 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2993,10 +2993,17 @@ bool GlobalOpt::OptimizeGlobalAliases(Module &M) {
 
   for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end();
        I != E;) {
-    Module::alias_iterator J = I++;
+    GlobalAlias *J = &*I++;
+
     // Aliases without names cannot be referenced outside this module.
     if (!J->hasName() && !J->isDeclaration() && !J->hasLocalLinkage())
       J->setLinkage(GlobalValue::InternalLinkage);
+
+    if (deleteIfDead(*J)) {
+      Changed = true;
+      continue;
+    }
+
     // If the aliasee may change at link time, nothing can be done - bail out.
     if (J->mayBeOverridden())
       continue;
diff --git a/test/Transforms/GlobalOpt/alias-resolve.ll b/test/Transforms/GlobalOpt/alias-resolve.ll
index f11fdb5e2bb..46b90ec29b9 100644
--- a/test/Transforms/GlobalOpt/alias-resolve.ll
+++ b/test/Transforms/GlobalOpt/alias-resolve.ll
@@ -13,8 +13,8 @@
 ; CHECK: @weak1 = weak alias void (), void ()* @bar2
 
 @bar4 = private unnamed_addr constant [2 x i8*] zeroinitializer
-@foo4 = linkonce_odr unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @bar4, i32 0, i32 1)
-; CHECK: @foo4 = linkonce_odr unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @bar4, i32 0, i32 1)
+@foo4 = weak_odr unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @bar4, i32 0, i32 1)
+; CHECK: @foo4 = weak_odr unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @bar4, i32 0, i32 1)
 
 define void @bar2() {
   ret void
diff --git a/test/Transforms/GlobalOpt/deadglobal.ll b/test/Transforms/GlobalOpt/deadglobal.ll
index 9563a23b2c2..f5eed44cbb6 100644
--- a/test/Transforms/GlobalOpt/deadglobal.ll
+++ b/test/Transforms/GlobalOpt/deadglobal.ll
@@ -1,11 +1,14 @@
 ; RUN: opt < %s -globalopt -S | FileCheck %s
 
 @G1 = internal global i32 123            ; <i32*> [#uses=1]
+@A1 = internal alias i32, i32* @G1
 
 ; CHECK-NOT: @G1
 ; CHECK: @G2
 ; CHECK-NOT: @G3
 
+; CHECK-NOT: @A1
+
 define void @foo1() {
 ; CHECK: define void @foo
 ; CHECK-NEXT: ret
diff --git a/test/Transforms/GlobalOpt/localize-constexpr.ll b/test/Transforms/GlobalOpt/localize-constexpr.ll
index 6754533a50c..3fa7db89b04 100644
--- a/test/Transforms/GlobalOpt/localize-constexpr.ll
+++ b/test/Transforms/GlobalOpt/localize-constexpr.ll
@@ -13,7 +13,7 @@ define i8 @f() norecurse {
 }
 
 @H = internal global i32 42
-@Halias = internal alias i32, i32* @H
+@Halias = alias i32, i32* @H
 
 ; @H can't be localized because @Halias uses it, and @Halias can't be converted to an instruction.
 define i8 @g() norecurse {