[PATCH] D96811: [CSSPGO][llvm-profgen] Change sample count of dangling probe in llvm-profgen

[Lei Wang via Phabricator via llvm-commits]

wlei created this revision.
Herald added subscribers: hoy, wenlei, lxfind.
wlei requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D96811

Files:
  llvm/test/tools/llvm-profgen/inline-cs-pseudoprobe.test
  llvm/test/tools/llvm-profgen/noinline-cs-pseudoprobe.test
  llvm/tools/llvm-profgen/ProfileGenerator.cpp


Index: llvm/tools/llvm-profgen/ProfileGenerator.cpp
===================================================================
--- llvm/tools/llvm-profgen/ProfileGenerator.cpp
+++ llvm/tools/llvm-profgen/ProfileGenerator.cpp
@@ -492,7 +492,16 @@
     FunctionSamples &FunctionProfile =
         getFunctionProfileForLeafProbe(ContextStrStack, Probe, Binary);
 
-    FunctionProfile.addBodySamples(Probe->Index, 0, Count);
+    // Use UINT64_MAX to mark sample count for a dangling probe
+    // Dangling probes are the probes associated to an empty block. With this
+    // place holder, sample count on dangling probe will not be trusted by the
+    // compiler and it will rely on the counts inference algorithm to get the
+    // probe a reasonable count.
+    if (Probe->isDangling())
+      FunctionProfile.addBodySamples(Probe->Index, 0, UINT64_MAX);
+    else
+      FunctionProfile.addBodySamples(Probe->Index, 0, Count);
+
     FunctionProfile.addTotalSamples(Count);
     if (Probe->isEntry()) {
       FunctionProfile.addHeadSamples(Count);
Index: llvm/test/tools/llvm-profgen/noinline-cs-pseudoprobe.test
===================================================================
--- llvm/test/tools/llvm-profgen/noinline-cs-pseudoprobe.test
+++ llvm/test/tools/llvm-profgen/noinline-cs-pseudoprobe.test
@@ -10,8 +10,8 @@
 ; CHECK-NEXT: !CFGChecksum: 138950591924
 ; CHECK-NEXT:[main:2 @ foo:8 @ bar]:60:15
 ; CHECK-NEXT: 1: 15
-; CHECK-NEXT: 2: 15
-; CHECK-NEXT: 3: 15
+; CHECK-NEXT: 2: 18446744073709551615
+; CHECK-NEXT: 3: 18446744073709551615
 ; CHECK-NEXT: 4: 15
 ; CHECK-NEXT: !CFGChecksum: 72617220756
 
Index: llvm/test/tools/llvm-profgen/inline-cs-pseudoprobe.test
===================================================================
--- llvm/test/tools/llvm-profgen/inline-cs-pseudoprobe.test
+++ llvm/test/tools/llvm-profgen/inline-cs-pseudoprobe.test
@@ -11,8 +11,8 @@
 ; CHECK-NEXT: !CFGChecksum: 138950591924
 ; CHECK-NEXT:[main:2 @ foo:8 @ bar]:56:14
 ; CHECK-NEXT: 1: 14
-; CHECK-NEXT: 2: 14
-; CHECK-NEXT: 3: 14
+; CHECK-NEXT: 2: 18446744073709551615
+; CHECK-NEXT: 3: 18446744073709551615
 ; CHECK-NEXT: 4: 14
 ; CHECK-NEXT: !CFGChecksum: 72617220756
 


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