AMDGPU/SI: Handle aliases in AMDGPUAlwaysInlinePass

Summary:
Simply replace usage of aliases to functions with aliasee.
This came up when bitcode linking to builtin library and
calls to aliases not being resolved.

Also made minor improvements to existing test.

Reviewers: tstellarAMD, alex-t, vpykhtin

Subscribers: arsenm, wdng, rampitec

Differential Revision: https://reviews.llvm.org/D24023

llvm-svn: 280221
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAlwaysInlinePass.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAlwaysInlinePass.cpp
index 63f5fb3..886b1b0 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAlwaysInlinePass.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAlwaysInlinePass.cpp
@@ -35,8 +35,20 @@
 char AMDGPUAlwaysInline::ID = 0;
 
 bool AMDGPUAlwaysInline::runOnModule(Module &M) {
+  std::vector<GlobalAlias*> AliasesToRemove;
   std::vector<Function *> FuncsToClone;
 
+  for (GlobalAlias &A : M.aliases()) {
+    if (Function* F = dyn_cast<Function>(A.getAliasee())) {
+      A.replaceAllUsesWith(F);
+      AliasesToRemove.push_back(&A);
+    }
+  }
+
+  for (GlobalAlias* A : AliasesToRemove) {
+    A->eraseFromParent();
+  }
+
   for (Function &F : M) {
     if (!F.hasLocalLinkage() && !F.isDeclaration() && !F.use_empty() &&
         !F.hasFnAttribute(Attribute::NoInline))