r298429 - Clang change: Do not inline hot callsites for samplepgo in thinlto compile phase.

[Dehao Chen via cfe-commits]

Author: dehao
Date: Tue Mar 21 14:55:46 2017
New Revision: 298429

URL: http://llvm.org/viewvc/llvm-project?rev=298429&view=rev
Log:
Clang change: Do not inline hot callsites for samplepgo in thinlto compile phase.

Summary:
Because SamplePGO passes will be invoked twice in ThinLTO build: once at compile phase, the other at backend. We want to make sure the IR at the 2nd phase matches the hot part in pro
file, thus we do not want to inline hot callsites in the first phase.

Reviewers: tejohnson, eraman

Reviewed By: tejohnson

Subscribers: mehdi_amini, cfe-commits, Prazek

Differential Revision: https://reviews.llvm.org/D31202

Added:
    cfe/trunk/test/CodeGen/Inputs/pgo-sample-thinlto-summary.prof
    cfe/trunk/test/CodeGen/pgo-sample-thinlto-summary.c
Modified:
    cfe/trunk/lib/CodeGen/BackendUtil.cpp

Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/BackendUtil.cpp?rev=298429&r1=298428&r2=298429&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/BackendUtil.cpp (original)
+++ cfe/trunk/lib/CodeGen/BackendUtil.cpp Tue Mar 21 14:55:46 2017
@@ -318,8 +318,13 @@ void EmitAssemblyHelper::CreatePasses(le
                                      !CodeGenOpts.DisableLifetimeMarkers);
     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
   } else {
+    // We do not want to inline hot callsites for SamplePGO module-summary build
+    // because profile annotation will happen again in ThinLTO backend, and we
+    // want the IR of the hot path to match the profile.
     PMBuilder.Inliner = createFunctionInliningPass(
-        CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize);
+        CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
+        (!CodeGenOpts.SampleProfileFile.empty() &&
+         CodeGenOpts.EmitSummaryIndex));
   }
 
   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;

Added: cfe/trunk/test/CodeGen/Inputs/pgo-sample-thinlto-summary.prof
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/Inputs/pgo-sample-thinlto-summary.prof?rev=298429&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/Inputs/pgo-sample-thinlto-summary.prof (added)
+++ cfe/trunk/test/CodeGen/Inputs/pgo-sample-thinlto-summary.prof Tue Mar 21 14:55:46 2017
@@ -0,0 +1,2 @@
+bar:100:100
+ 2: 2000 foo:2000

Added: cfe/trunk/test/CodeGen/pgo-sample-thinlto-summary.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/pgo-sample-thinlto-summary.c?rev=298429&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/pgo-sample-thinlto-summary.c (added)
+++ cfe/trunk/test/CodeGen/pgo-sample-thinlto-summary.c Tue Mar 21 14:55:46 2017
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -O2 -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -o - 2>&1 | FileCheck %s -check-prefix=INLINE
+// RUN: %clang_cc1 -O2 -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -flto=thin -o - 2>&1 | FileCheck %s -check-prefix=NOINLINE
+// Checks if hot call is inlined by normal compile, but not inlined by
+// thinlto compile.
+
+int baz(int);
+int g;
+
+void foo(int n) {
+  for (int i = 0; i < n; i++)
+    g += baz(i);
+}
+
+// INLINE-NOT: call{{.*}}foo
+// NOINLINE: call{{.*}}foo
+void bar(int n) {
+  for (int i = 0; i < n; i++)
+    foo(i);
+}