[PATCH] D150741: [FS-AFDO] Clean up non-zero discriminator for pseudo probes at the first FS discriminator pass.

[Hongtao Yu via Phabricator via llvm-commits]

hoy updated this revision to Diff 522859.
hoy edited the summary of this revision.
hoy added a comment.

Updating D150741 <https://reviews.llvm.org/D150741>: [FS-AFDO] Clean up non-zero discriminator for pseudo probes at the first FS discriminator pass.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150741/new/

https://reviews.llvm.org/D150741

Files:
  llvm/include/llvm/CodeGen/MIRFSDiscriminator.h
  llvm/lib/CodeGen/MIRFSDiscriminator.cpp
  llvm/test/CodeGen/X86/fsafdo_probe.ll


Index: llvm/test/CodeGen/X86/fsafdo_probe.ll
===================================================================
--- llvm/test/CodeGen/X86/fsafdo_probe.ll
+++ llvm/test/CodeGen/X86/fsafdo_probe.ll
@@ -65,7 +65,8 @@
 !6 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 5, type: !7, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !2)
 !7 = !DISubroutineType(types: !2)
 !8 = !DILocation(line: 7, column: 15, scope: !9)
-!9 = !DILexicalBlockFile(scope: !6, file: !1, discriminator: 0)
+;; The discriminator with value 2 is to test that it can be cleaned up by the first FS discriminator pass.
+!9 = !DILexicalBlockFile(scope: !6, file: !1, discriminator: 2)
 !10 = !DILocation(line: 7, column: 3, scope: !9)
 !11 = !DILocation(line: 9, column: 5, scope: !9)
 !12 = !DILocation(line: 14, column: 3, scope: !6)
Index: llvm/lib/CodeGen/MIRFSDiscriminator.cpp
===================================================================
--- llvm/lib/CodeGen/MIRFSDiscriminator.cpp
+++ llvm/lib/CodeGen/MIRFSDiscriminator.cpp
@@ -150,6 +150,12 @@
       if (LineNo == 0)
         continue;
       unsigned Discriminator = DIL->getDiscriminator();
+      // Clean up discriminators for pseudo probes at the first FS discriminator
+      // pass as their discriminators should not ever be used.
+      if ((Pass == FSDiscriminatorPass::Pass1) && I.isPseudoProbe()) {
+        Discriminator = 0;
+        I.setDebugLoc(DIL->cloneWithDiscriminator(0));
+      }
       uint64_t CallStackHashVal = 0;
       if (ImprovedFSDiscriminator)
         CallStackHashVal = getCallStackHash(DIL);
Index: llvm/include/llvm/CodeGen/MIRFSDiscriminator.h
===================================================================
--- llvm/include/llvm/CodeGen/MIRFSDiscriminator.h
+++ llvm/include/llvm/CodeGen/MIRFSDiscriminator.h
@@ -31,6 +31,7 @@
 using namespace sampleprof;
 class MIRAddFSDiscriminators : public MachineFunctionPass {
   MachineFunction *MF = nullptr;
+  FSDiscriminatorPass Pass;
   unsigned LowBit;
   unsigned HighBit;
 
@@ -38,7 +39,7 @@
   static char ID;
   /// PassNum is the sequence number this pass is called, start from 1.
   MIRAddFSDiscriminators(FSDiscriminatorPass P = FSDiscriminatorPass::Pass1)
-      : MachineFunctionPass(ID) {
+      : MachineFunctionPass(ID), Pass(P) {
     LowBit = getFSPassBitBegin(P);
     HighBit = getFSPassBitEnd(P);
     assert(LowBit < HighBit && "HighBit needs to be greater than Lowbit");


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