[PATCH] D38763: Include already promoted counts when computing SUM for VP.

Dehao Chen via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Oct 10 14:21:27 PDT 2017


danielcdh created this revision.
Herald added a subscriber: sanjoy.

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.


https://reviews.llvm.org/D38763

Files:
  lib/Transforms/IPO/SampleProfile.cpp
  test/Transforms/SampleProfile/indirect-call.ll


Index: test/Transforms/SampleProfile/indirect-call.ll
===================================================================
--- test/Transforms/SampleProfile/indirect-call.ll
+++ test/Transforms/SampleProfile/indirect-call.ll
@@ -182,7 +182,7 @@
 ; 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)
Index: lib/Transforms/IPO/SampleProfile.cpp
===================================================================
--- lib/Transforms/IPO/SampleProfile.cpp
+++ lib/Transforms/IPO/SampleProfile.cpp
@@ -1155,24 +1155,20 @@
   }
 }
 
-/// 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
@@ -1265,8 +1261,10 @@
           auto T = FS->findCallTargetMapAt(LineOffset, Discriminator);
           if (!T || T.get().size() == 0)
             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());


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