[AlwaysInliner] Emit optimization remarks

[aeubanks]

Summary

To match the normal inliner in preparation for https://reviews.llvm.org/D86988.

Also change a FIXME to an assert.

[davidxl]

llvm/lib/Transforms/IPO/AlwaysInliner.cpp

72

Add an assertion reason string.

[aeubanks]

add assertion reason string

[davidxl]

lgtm

llvm/lib/Transforms/IPO/AlwaysInliner.cpp

if (!F.isDeclaration() && F.hasFnAttribute(Attribute::AlwaysInline) &&
         isInlineViable(F).isSuccess()) {
       Calls.clear();
 
       for (User *U : F.users())
         if (auto *CB = dyn_cast<CallBase>(U))
           if (CB->getCalledFunction() == &F)
             Calls.insert(CB);
 
-      for (CallBase *CB : Calls)
-        // FIXME: We really shouldn't be able to fail to inline at this point!
-        // We should do something to log or check the inline failures here.
-        Changed |=
-            InlineFunction(*CB, IFI, /*CalleeAAR=*/nullptr, InsertLifetime)
-                .isSuccess();
+      for (CallBase *CB : Calls) {
+        Function *Caller = CB->getCaller();
+        OptimizationRemarkEmitter ORE(Caller);
+        auto OIC = shouldInline(
+            *CB,
+            [&](CallBase &CB) {
+              return InlineCost::getAlways("always inline attribute");
+            },
+            ORE);
+        assert(OIC);
+        emitInlinedInto(ORE, CB->getDebugLoc(), CB->getParent(), F, *Caller,
+                        *OIC, false, DEBUG_TYPE);
+
+        InlineResult Res =
+            InlineFunction(*CB, IFI, /*CalleeAAR=*/nullptr, InsertLifetime);
+        assert(Res.isSuccess() && "unexpected failure to inline");
+        (void)Res;
+        Changed = true;
+      }
 
       // Remember to try and delete this function afterward. This both avoids
       // re-walking the rest of the module and avoids dealing with any iterator
       // invalidation issues while deleting functions.
       InlinedFunctions.push_back(&F);
     }
 
   // Remove any live functions.

llvm/test/Transforms/Inline/optimization-remarks.ll

 ; RUN: opt < %s -inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -S 2>&1 | \
-; RUN:       FileCheck -check-prefix=CHECK -check-prefix=NO_HOTNESS %s
+; RUN:       FileCheck -check-prefixes=CHECK,NO_HOTNESS,ALWAYS %s
 ; RUN: opt < %s -inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 | \
-; RUN:       FileCheck -check-prefix=CHECK -check-prefix=HOTNESS %s
+; RUN:       FileCheck -check-prefixes=CHECK,HOTNESS,ALWAYS %s
+
+; RUN: opt < %s -passes=always-inline -pass-remarks=inline -pass-remarks-missed=inline \
+; RUN:       -pass-remarks-analysis=inline -S 2>&1 | \
+; RUN:       FileCheck -check-prefixes=ALWAYS %s
+; RUN: opt < %s -passes=always-inline -pass-remarks=inline -pass-remarks-missed=inline \
+; RUN:       -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 | \
+; RUN:       FileCheck -check-prefixes=ALWAYS %s
 
 ; RUN: opt < %s -passes=inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -S 2>&1 | \
-; RUN:       FileCheck -check-prefix=CHECK -check-prefix=NO_HOTNESS %s
+; RUN:       FileCheck -check-prefixes=CHECK,NO_HOTNESS,ALWAYS %s
 ; RUN: opt < %s -passes=inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 | \
-; RUN:       FileCheck -check-prefix=CHECK -check-prefix=HOTNESS %s
+; RUN:       FileCheck -check-prefixes=CHECK,HOTNESS,ALWAYS %s
 
 ; RUN: opt < %s -passes=inliner-wrapper -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -S 2>&1 | \
-; RUN:       FileCheck -check-prefix=CHECK -check-prefix=NO_HOTNESS %s
+; RUN:       FileCheck -check-prefixes=CHECK,NO_HOTNESS,ALWAYS %s
 ; RUN: opt < %s -passes=inliner-wrapper -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 | \
-; RUN:       FileCheck -check-prefix=CHECK -check-prefix=HOTNESS %s
+; RUN:       FileCheck -check-prefixes=CHECK,HOTNESS,ALWAYS %s
 
-; HOTNESS: fox will not be inlined into bar because its definition is unavailable
+; HOTNESS-DAG: fox will not be inlined into bar because its definition is unavailable
 ; NO_HOTNESS-NOT: fox will not be inlined into bar because its definition is unavailable
-; CHECK: foo inlined into bar with (cost=always): always inline attribute
-; CHECK: foz not inlined into bar because it should never be inlined (cost=never): noinline function attribute
+; ALWAYS-DAG: foo inlined into bar with (cost=always): always inline attribute
+; CHECK-DAG: foz not inlined into bar because it should never be inlined (cost=never): noinline function attribute
 
 ; Function Attrs: alwaysinline nounwind uwtable
 define i32 @foo(i32 %x, i32 %y) #0 !prof !1 {
 entry:
   %x.addr = alloca i32, align 4
   %y.addr = alloca i32, align 4
   store i32 %x, i32* %x.addr, align 4
   store i32 %y, i32* %y.addr, align 4