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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280221 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/AMDGPU/AMDGPUAlwaysInlinePass.cpp

@@ -35,8 +35,20 @@ class AMDGPUAlwaysInline : public ModulePass {
 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))

test/CodeGen/AMDGPU/inline-calls.ll

@@ -10,6 +10,7 @@ entry:
 }
 
 ; CHECK: {{^}}kernel:
+; CHECK-NOT: call
 define void @kernel(i32 addrspace(1)* %out) {
 entry:
   %tmp0 = call i32 @func(i32 1)
@@ -18,8 +19,32 @@ entry:
 }
 
 ; CHECK: {{^}}kernel2:
+; CHECK-NOT: call
 define void @kernel2(i32 addrspace(1)* %out) {
 entry:
   call void @kernel(i32 addrspace(1)* %out)
   ret void
 }
+
+; CHECK-NOT: func_alias
+@func_alias = alias i32 (i32), i32 (i32)* @func
+
+; CHECK: {{^}}kernel3:
+; CHECK-NOT: call
+define void @kernel3(i32 addrspace(1)* %out) {
+entry:
+  %tmp0 = call i32 @func_alias(i32 1)
+  store i32 %tmp0, i32 addrspace(1)* %out
+  ret void
+}
+
+; CHECK-NOT: kernel_alias
+@kernel_alias = alias void (i32 addrspace(1)*), void (i32 addrspace(1)*)* @kernel
+
+; CHECK: {{^}}kernel4:
+; CHECK-NOT: call
+define void @kernel4(i32 addrspace(1)* %out) {
+entry:
+  call void @kernel_alias(i32 addrspace(1)* %out)
+  ret void
+}