Attach maximum function count to Module when using PGO mode

This sets the maximum entry count among all functions in the program to the
module using module flags. This allows the optimizer to use this information.

Differential Revision: http://reviews.llvm.org/D15163

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@255397 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 29c5f3eed5ace2f653ec9d168738ae08f74f9db5..8d7254904a9d2a17f17792a3dd13442e3a1abf48 100644 (file)
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -376,6 +376,9 @@ void CodeGenModule::Release() {
   }
   if (PGOReader && PGOStats.hasDiagnostics())
     PGOStats.reportDiagnostics(getDiags(), getCodeGenOpts().MainFileName);
+  // In PGO mode, attach maximum function count to the module.
+  if (PGOReader)
+    getModule().setMaximumFunctionCount(PGOReader->getMaximumFunctionCount());
   EmitCtorList(GlobalCtors, "llvm.global_ctors");
   EmitCtorList(GlobalDtors, "llvm.global_dtors");
   EmitGlobalAnnotations();

diff --git a/test/CodeGen/pgo-max-function-count.c b/test/CodeGen/pgo-max-function-count.c
new file mode 100644 (file)
index 0000000..b60a467
--- /dev/null
+++ b/test/CodeGen/pgo-max-function-count.c
@@ -0,0 +1,9 @@
+// RUN: %clang -fprofile-generate -o %t -O2 %s
+// RUN: env LLVM_PROFILE_FILE=%t.profraw  %t
+// RUN: llvm-profdata merge -o %t.profdata %t.profraw
+// RUN: %clang -fprofile-use=%t.profdata -o - -S -emit-llvm %s | FileCheck %s
+// Check
+int main() {
+  return 0;
+}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"MaxFunctionCount", i32 1}