[Inliner] Respect noinline call site attribute

[xbolva00]

Summary

always_inline foo() { }

bar () {

noinline foo();
}

We should prefer call site attribute over attribute on decl.

Related to https://reviews.llvm.org/D119061

[aeubanks]

llvm/lib/Analysis/InlineCost.cpp

2867

checking the call site attributes with Call.getAttributes().hasFnAttr(Attribute::NoInline) should be enough since noinline and alwaysinline are incompatible within a set of attriutes

[xbolva00]

Addressed review comment

llvm/lib/Analysis/InlineCost.cpp

       if (PTy->getAddressSpace() != AllocaAS)
         return InlineResult::failure("byval arguments without alloca"
                                      " address space");
     }
 
   // Calls to functions with always-inline attributes should be inlined
   // whenever possible.
   if (Call.hasFnAttr(Attribute::AlwaysInline)) {
+    if (Callee->hasFnAttribute(Attribute::AlwaysInline) && Call.isNoInline())
+      return InlineResult::failure("noinline call site attribute");
+
     auto IsViable = isInlineViable(*Callee);
     if (IsViable.isSuccess())
       return InlineResult::success();
     return InlineResult::failure(IsViable.getFailureReason());
   }
 
   // Never inline functions with conflicting attributes (unless callee has
   // always-inline attribute).

llvm/test/Transforms/Inline/call-site-attrs.ll

+; RUN: opt < %s -inline -S | FileCheck %s
+; RUN: opt < %s -passes='cgscc(inline)' -S | FileCheck %s
+
+; Always prefer call site attribute over function attribute
+
+define internal i32 @inner1() {
+; CHECK: @inner1(
+  ret i32 1
+}
+
+define i32 @outer1() {
+; CHECK-LABEL: @outer1(
+; CHECK: call
+
+   %r = call i32 @inner1() noinline
+   ret i32 %r
+}
+
+define internal i32 @inner2() alwaysinline {
+; CHECK: @inner2(
+  ret i32 1
+}
+
+define i32 @outer2() {
+; CHECK-LABEL: @outer2(
+; CHECK: call
+
+   %r = call i32 @inner2() noinline
+   ret i32 %r
+}
+
+define i32 @inner3() alwaysinline {
+; CHECK: @inner3(
+  ret i32 1
+}
+
+define i32 @outer3() {
+; CHECK-LABEL: @outer3(
+; CHECK: call
+
+   %r = call i32 @inner3() noinline
+   ret i32 %r
+}
+
+define i32 @inner4() noinline {
+; CHECK: @inner4(
+  ret i32 1
+}
+
+define i32 @outer4() {
+; CHECK-LABEL: @outer4(
+; CHECK-NOT: call
+; CHECK: ret
+
+   %r = call i32 @inner4() alwaysinline
+
+   ret i32 %r
+}
+