From 561a742524fc0e97f2c9aa5465b85d0e3bb9862c Mon Sep 17 00:00:00 2001
From: Dehao Chen <dehao@google.com>
Date: Mon, 6 Nov 2017 19:52:49 +0000
Subject: [PATCH] Include already promoted counts when computing SUM for VP.

Summary: When computing the SUM for indirect call promotion, if the callsite is already promoted in the profile, it will be promoted before ICP. In the current implementation, ICP only sees remaining counts in SUM. This may cause extra indirect call targets being promoted. This patch updates the SUM to include the counts already promoted earlier. This way we do not end up promoting too many indirect call targets.

Reviewers: tejohnson

Reviewed By: tejohnson

Subscribers: llvm-commits, sanjoy

Differential Revision: https://reviews.llvm.org/D38763

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317502 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/SampleProfile.cpp          | 26 +++++++++----------
 .../Transforms/SampleProfile/indirect-call.ll |  2 +-
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/lib/Transforms/IPO/SampleProfile.cpp b/lib/Transforms/IPO/SampleProfile.cpp
index 34414f96cca..8930e9b2b95 100644
--- a/lib/Transforms/IPO/SampleProfile.cpp
+++ b/lib/Transforms/IPO/SampleProfile.cpp
@@ -1182,24 +1182,20 @@ void SampleProfileLoader::buildEdges(Function &F) {
   }
 }
 
-/// Sorts the CallTargetMap \p M by count in descending order and stores the
-/// sorted result in \p Sorted. Returns the total counts.
-static uint64_t SortCallTargets(SmallVector<InstrProfValueData, 2> &Sorted,
-                                const SampleRecord::CallTargetMap &M) {
-  Sorted.clear();
-  uint64_t Sum = 0;
-  for (auto I = M.begin(); I != M.end(); ++I) {
-    Sum += I->getValue();
-    Sorted.push_back({Function::getGUID(I->getKey()), I->getValue()});
-  }
-  std::sort(Sorted.begin(), Sorted.end(),
+/// Returns the sorted CallTargetMap \p M by count in descending order.
+static SmallVector<InstrProfValueData, 2> SortCallTargets(
+    const SampleRecord::CallTargetMap &M) {
+  SmallVector<InstrProfValueData, 2> R;
+  for (auto I = M.begin(); I != M.end(); ++I)
+    R.push_back({Function::getGUID(I->getKey()), I->getValue()});
+  std::sort(R.begin(), R.end(),
             [](const InstrProfValueData &L, const InstrProfValueData &R) {
               if (L.Count == R.Count)
                 return L.Value > R.Value;
               else
                 return L.Count > R.Count;
             });
-  return Sum;
+  return R;
 }
 
 /// \brief Propagate weights into edges
@@ -1292,8 +1288,10 @@ void SampleProfileLoader::propagateWeights(Function &F) {
           auto T = FS->findCallTargetMapAt(LineOffset, Discriminator);
           if (!T || T.get().empty())
             continue;
-          SmallVector<InstrProfValueData, 2> SortedCallTargets;
-          uint64_t Sum = SortCallTargets(SortedCallTargets, T.get());
+          SmallVector<InstrProfValueData, 2> SortedCallTargets =
+              SortCallTargets(T.get());
+          uint64_t Sum;
+          findIndirectCallFunctionSamples(I, Sum);
           annotateValueSite(*I.getParent()->getParent()->getParent(), I,
                             SortedCallTargets, Sum, IPVK_IndirectCallTarget,
                             SortedCallTargets.size());
diff --git a/test/Transforms/SampleProfile/indirect-call.ll b/test/Transforms/SampleProfile/indirect-call.ll
index 61a1bc51996..0c00639e6c0 100644
--- a/test/Transforms/SampleProfile/indirect-call.ll
+++ b/test/Transforms/SampleProfile/indirect-call.ll
@@ -182,7 +182,7 @@ define void @test_direct() !dbg !22 {
 ; CHECK: ![[PROF]] = !{!"VP", i32 0, i64 3457, i64 9191153033785521275, i64 2059, i64 -1069303473483922844, i64 1398}
 ; CHECK: ![[BR1]] = !{!"branch_weights", i32 4000, i32 4000}
 ; CHECK: ![[BR2]] = !{!"branch_weights", i32 3000, i32 1000}
-; CHECK: ![[VP]] = !{!"VP", i32 0, i64 1000, i64 -6391416044382067764, i64 1000}
+; CHECK: ![[VP]] = !{!"VP", i32 0, i64 8000, i64 -6391416044382067764, i64 1000}
 !6 = distinct !DISubprogram(name: "test_inline", scope: !1, file: !1, line: 6, unit: !0)
 !7 = !DILocation(line: 7, scope: !6)
 !8 = distinct !DISubprogram(name: "test_inline_strip", scope: !1, file: !1, line: 8, unit: !0)
-- 
2.40.0