From 6a27c48be223ce25b73eab7a49f4d502cdf24dce Mon Sep 17 00:00:00 2001
From: Taewook Oh <twoh@fb.com>
Date: Tue, 2 Apr 2019 15:48:21 +0000
Subject: [PATCH] [SampleProfile] Repeat indirect call promotion only when the
 target is actually hot.

Summary: It is possible that multiple indirect call targets have been promoted for a single callsite from the profiled binary. Current implementation repeats promotion for all these targets as far as the callsite itself is hot (the callsite is assumed to be hot if any one of these targets was "hot" during the profiling). However, even when one of the ICPed target is hot other targets may not, and we should not repeat promotion for "cold" targets.

Reviewers: danielcdh, wmi

Subscribers: hiraditya, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59940

llvm-svn: 357484
---
 llvm/lib/Transforms/IPO/SampleProfile.cpp          |  3 +++
 .../SampleProfile/Inputs/cold-indirect-call.prof   |  6 +++++
 .../Transforms/SampleProfile/cold-indirect-call.ll | 31 ++++++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 llvm/test/Transforms/SampleProfile/Inputs/cold-indirect-call.prof
 create mode 100644 llvm/test/Transforms/SampleProfile/cold-indirect-call.ll

diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index f3bad36..b6ea014 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -834,6 +834,9 @@ bool SampleProfileLoader::inlineHotFunctions(
           if (CalleeFunctionName == F.getName())
             continue;
 
+          if (!callsiteIsHot(FS, PSI))
+            continue;
+
           const char *Reason = "Callee function not available";
           auto R = SymbolMap.find(CalleeFunctionName);
           if (R != SymbolMap.end() && R->getValue() &&
diff --git a/llvm/test/Transforms/SampleProfile/Inputs/cold-indirect-call.prof b/llvm/test/Transforms/SampleProfile/Inputs/cold-indirect-call.prof
new file mode 100644
index 0000000..636ed7e
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/Inputs/cold-indirect-call.prof
@@ -0,0 +1,6 @@
+foo:5000:1
+ 1: 2000 quz:1000
+ 1: bar:3000
+   1: 3000
+ 1: baz:0
+   1: 0
diff --git a/llvm/test/Transforms/SampleProfile/cold-indirect-call.ll b/llvm/test/Transforms/SampleProfile/cold-indirect-call.ll
new file mode 100644
index 0000000..b8a61e0
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/cold-indirect-call.ll
@@ -0,0 +1,31 @@
+; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/cold-indirect-call.prof -S | FileCheck %s
+; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/cold-indirect-call.prof -S | FileCheck %s
+
+define i32 @foo(i32 ()* %func) !dbg !3 {
+; CHECK: icmp {{.*}} @bar
+; CHECK-NOT: icmp {{.*}} @baz
+  %call = call i32 %func(), !dbg !4
+  ret i32 %call
+}
+
+define i32 @bar() !dbg !5 {
+  ret i32 41, !dbg !6
+}
+
+define i32 @baz() !dbg !7 {
+  ret i32 42, !dbg !8
+}
+
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1)
+!1 = !DIFile(filename: "foo.cc", directory: "/")
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 4, unit: !0)
+!4 = !DILocation(line: 5, scope: !3)
+!5 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 8, unit: !0)
+!6 = !DILocation(line: 9, scope: !5)
+!7 = distinct !DISubprogram(name: "baz", scope: !1, file: !1, line: 12, unit: !0)
+!8 = !DILocation(line: 13, scope: !7)
-- 
2.7.4