[PATCH] Generate cold attribute for functions marked __atribute__((cold))

This removes a FIXME in CodeGenModule::SetLLVMFunctionAttributesForDefinition.
When a function is declared cold we can now generate the IR attribute in
addition to marking the function to be optimized for size.

I tried adding a separate CHECK in the existing test, but it was
failing.  I suppose CHECK matches one line exactly once?  This would be
a problem if the attributes are listed in a different order, though they
seem to be sorted.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182666 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CodeGenModule.cpp

@@ -620,9 +620,10 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
     B.addAttribute(llvm::Attribute::AlwaysInline);
   }
 
-  // FIXME: Communicate hot and cold attributes to LLVM more directly.
-  if (D->hasAttr<ColdAttr>())
+  if (D->hasAttr<ColdAttr>()) {
     B.addAttribute(llvm::Attribute::OptimizeForSize);
+    B.addAttribute(llvm::Attribute::Cold);
+  }
 
   if (D->hasAttr<MinSizeAttr>())
     B.addAttribute(llvm::Attribute::MinSize);

test/CodeGen/attr-coldhot.c

@@ -8,4 +8,4 @@ int test1() __attribute__((__cold__)) {
 // CHECK: ret
 }
 
-// CHECK: attributes [[ATTR]] = { {{.*}}optsize{{.*}} }
+// CHECK: attributes [[ATTR]] = { {{.*}}cold{{.*}}optsize{{.*}} }