[AMDGPU] Exclude always_inline from max bb threshold

[rampitec]

Summary

Honor always_inline attribute when processing -amdgpu-inline-max-bb.
It was lost during the ports of the heuristic. There is no reason
to honor inline hint, but not always inline.

llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp

bool GCNTTIImpl::areInlineCompatible(const Function *Caller,
 
   // FIXME: dx10_clamp can just take the caller setting, but there seems to be
   // no way to support merge for backend defined attributes.
   AMDGPU::SIModeRegisterDefaults CallerMode(*Caller);
   AMDGPU::SIModeRegisterDefaults CalleeMode(*Callee);
   if (!CallerMode.isInlineCompatible(CalleeMode))
     return false;
 
+  if (Callee->hasFnAttribute(Attribute::AlwaysInline) ||
+      Callee->hasFnAttribute(Attribute::InlineHint))
+    return true;
+
   // Hack to make compile times reasonable.
-  if (InlineMaxBB && !Callee->hasFnAttribute(Attribute::InlineHint)) {
+  if (InlineMaxBB) {
     // Single BB does not increase total BB amount.
     if (Callee->size() == 1)
       return true;
     size_t BBSize = Caller->size() + Callee->size() - 1;
     return BBSize <= InlineMaxBB;
   }
 
   return true;