[PATCH] D149597: [FS-AFDO] Do not load non-FS profil in MIR loader.

[Hongtao Yu via Phabricator via llvm-commits]

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I was seeing a regression when enabling FS discriminators on an non-FS CSSPGO build. This is because a probe can get a zero-valued discriminator at a specific pass and that could lead to accidentally loading the corresponding base counter in the non-FS profile, while a non-zeo discriminator would end up getting zero samples. This could in turn undo the sample distribution effort done by previous BFI maintenance work and the probe distribution factor work for pseudo probes specifically. To mitigate that I'm disabling loading a non-FS profile against FS discriminators. The problem should also exist with non-CS AutoFDO, so I'm doing this for it too.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D149597

Files:
  llvm/include/llvm/ProfileData/SampleProfReader.h
  llvm/lib/CodeGen/MIRSampleProfile.cpp
  llvm/test/CodeGen/X86/fsafdo_test2.ll
  llvm/test/CodeGen/X86/fsafdo_test3.ll


Index: llvm/test/CodeGen/X86/fsafdo_test3.ll
===================================================================
--- llvm/test/CodeGen/X86/fsafdo_test3.ll
+++ llvm/test/CodeGen/X86/fsafdo_test3.ll
@@ -1,7 +1,7 @@
 ; RUN: llvm-profdata merge --sample -profile-isfs -o %t0.afdo %S/Inputs/fsloader.afdo
-; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=false -fs-profile-file=%t0.afdo -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false -print-machine-bfi -print-bfi-func-name=foo -print-before=fs-profile-loader -stop-after=fs-profile-loader < %s 2>&1 | FileCheck %s --check-prefixes=BFI,BFIV0
+; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=false -profile-isfs -fs-profile-file=%t0.afdo -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false -print-machine-bfi -print-bfi-func-name=foo -print-before=fs-profile-loader -stop-after=fs-profile-loader < %s 2>&1 | FileCheck %s --check-prefixes=BFI,BFIV0
 ; RUN: llvm-profdata merge --sample -profile-isfs -o %t1.afdo %S/Inputs/fsloader_v1.afdo
-; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=true -fs-profile-file=%t1.afdo -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false -print-machine-bfi -print-bfi-func-name=foo -print-before=fs-profile-loader -stop-after=fs-profile-loader < %s 2>&1 | FileCheck %s --check-prefixes=BFI,BFIV1
+; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=true -profile-isfs -fs-profile-file=%t1.afdo -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false -print-machine-bfi -print-bfi-func-name=foo -print-before=fs-profile-loader -stop-after=fs-profile-loader < %s 2>&1 | FileCheck %s --check-prefixes=BFI,BFIV1
 ;
 ;;
 ;; C source code for the test (compiler at -O3):
Index: llvm/test/CodeGen/X86/fsafdo_test2.ll
===================================================================
--- llvm/test/CodeGen/X86/fsafdo_test2.ll
+++ llvm/test/CodeGen/X86/fsafdo_test2.ll
@@ -1,10 +1,10 @@
 ; REQUIRES: asserts
 ; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=false < %s | FileCheck %s --check-prefixes=V0,V01
 ; RUN: llvm-profdata merge --sample -profile-isfs -o %t0.afdo %S/Inputs/fsloader.afdo
-; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=false -fs-profile-file=%t0.afdo -show-fs-branchprob -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false < %s 2>&1 | FileCheck %s --check-prefixes=LOADERV0,LOADER
+; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=false -profile-isfs -fs-profile-file=%t0.afdo -show-fs-branchprob -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false < %s 2>&1 | FileCheck %s --check-prefixes=LOADERV0,LOADER
 ; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=true < %s | FileCheck %s --check-prefixes=V1,V01
 ; RUN: llvm-profdata merge --sample -profile-isfs -o %t1.afdo %S/Inputs/fsloader_v1.afdo
-; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=true -fs-profile-file=%t1.afdo -show-fs-branchprob -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false < %s 2>&1 | FileCheck %s --check-prefixes=LOADERV1,LOADER
+; RUN: llc -enable-fs-discriminator -improved-fs-discriminator=true -profile-isfs -fs-profile-file=%t1.afdo -show-fs-branchprob -disable-ra-fsprofile-loader=false -disable-layout-fsprofile-loader=false < %s 2>&1 | FileCheck %s --check-prefixes=LOADERV1,LOADER
 ;
 ;;
 ;; C source code for the test (compiler at -O3):
Index: llvm/lib/CodeGen/MIRSampleProfile.cpp
===================================================================
--- llvm/lib/CodeGen/MIRSampleProfile.cpp
+++ llvm/lib/CodeGen/MIRSampleProfile.cpp
@@ -294,7 +294,7 @@
 
   Reader = std::move(ReaderOrErr.get());
   Reader->setModule(&M);
-  ProfileIsValid = (Reader->read() == sampleprof_error::success);
+  ProfileIsValid = (Reader->read() == sampleprof_error::success) && (Reader->profileIsFS());
 
   // Load pseudo probe descriptors for probe-based function samples.
   if (Reader->profileIsProbeBased()) {
Index: llvm/include/llvm/ProfileData/SampleProfReader.h
===================================================================
--- llvm/include/llvm/ProfileData/SampleProfReader.h
+++ llvm/include/llvm/ProfileData/SampleProfReader.h
@@ -483,6 +483,9 @@
   /// Whether input profile contains ShouldBeInlined contexts.
   bool profileIsPreInlined() const { return ProfileIsPreInlined; }
 
+  /// Whether input profile is flow-sensitive.
+  bool profileIsFS() const { return ProfileIsFS; }
+
   virtual std::unique_ptr<ProfileSymbolList> getProfileSymbolList() {
     return nullptr;
   };


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