[llvm] [PseudoProbe] Add an option to remove pseudo probes after profile annotation (PR #90293)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Lei Wang (wlei-llvm)

<details>
<summary>Changes</summary>

This can be used for testing perf overhead of pseudo-probe.

---
Full diff: https://github.com/llvm/llvm-project/pull/90293.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/IPO/SampleProfile.cpp (+22-3) 
- (modified) llvm/test/Transforms/SampleProfile/pseudo-probe-profile.ll (+6-2) 


``````````diff
diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index 0b3a6931e779b6..4b92b993ee268d 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -252,20 +252,21 @@ static cl::opt<unsigned> PrecentMismatchForStalenessError(
 
 static cl::opt<bool> CallsitePrioritizedInline(
     "sample-profile-prioritized-inline", cl::Hidden,
-
     cl::desc("Use call site prioritized inlining for sample profile loader."
              "Currently only CSSPGO is supported."));
 
 static cl::opt<bool> UsePreInlinerDecision(
     "sample-profile-use-preinliner", cl::Hidden,
-
     cl::desc("Use the preinliner decisions stored in profile context."));
 
 static cl::opt<bool> AllowRecursiveInline(
     "sample-profile-recursive-inline", cl::Hidden,
-
     cl::desc("Allow sample loader inliner to inline recursive calls."));
 
+static cl::opt<bool> RemoveProbeAfterProfileAnnotation(
+    "sample-profile-remove-probe", cl::Hidden, cl::init(false),
+    cl::desc("Remove pseudo-probe after sample profile annotation."));
+
 static cl::opt<std::string> ProfileInlineReplayFile(
     "sample-profile-inline-replay", cl::init(""), cl::value_desc("filename"),
     cl::desc(
@@ -518,6 +519,7 @@ class SampleProfileLoader final : public SampleProfileLoaderBaseImpl<Function> {
   void generateMDProfMetadata(Function &F);
   bool rejectHighStalenessProfile(Module &M, ProfileSummaryInfo *PSI,
                                   const SampleProfileMap &Profiles);
+  void removePseudoProbeInsts(Module &M);
 
   /// Map from function name to Function *. Used to find the function from
   /// the function name. If the function name contains suffix, additional
@@ -2127,6 +2129,20 @@ bool SampleProfileLoader::rejectHighStalenessProfile(
   return false;
 }
 
+void SampleProfileLoader::removePseudoProbeInsts(Module &M) {
+    for (Function &F : M) {
+      std::vector<Instruction *> InstsToDel;
+      for (auto &BB : F) {
+        for (auto &I : BB) {
+          if (isa<PseudoProbeInst>(&I))
+            InstsToDel.push_back(&I);
+        }
+      }
+      for (auto *I : InstsToDel)
+        I->eraseFromParent();
+    }
+}
+
 bool SampleProfileLoader::runOnModule(Module &M, ModuleAnalysisManager *AM,
                                       ProfileSummaryInfo *_PSI,
                                       LazyCallGraph &CG) {
@@ -2196,6 +2212,9 @@ bool SampleProfileLoader::runOnModule(Module &M, ModuleAnalysisManager *AM,
          notInlinedCallInfo)
       updateProfileCallee(pair.first, pair.second.entryCount);
 
+  if (RemoveProbeAfterProfileAnnotation && FunctionSamples::ProfileIsProbeBased)
+    removePseudoProbeInsts(M);
+
   return retval;
 }
 
diff --git a/llvm/test/Transforms/SampleProfile/pseudo-probe-profile.ll b/llvm/test/Transforms/SampleProfile/pseudo-probe-profile.ll
index 867a49dbaed2ee..7258ffca1278f3 100644
--- a/llvm/test/Transforms/SampleProfile/pseudo-probe-profile.ll
+++ b/llvm/test/Transforms/SampleProfile/pseudo-probe-profile.ll
@@ -1,5 +1,9 @@
-; RUN: opt < %s -passes=pseudo-probe,sample-profile -sample-profile-file=%S/Inputs/pseudo-probe-profile.prof -pass-remarks=sample-profile -pass-remarks-output=%t.opt.yaml -sample-profile-use-profi=0 -S | FileCheck %s
-; RUN: FileCheck %s -check-prefix=YAML < %t.opt.yaml
+; RUN: opt < %s -passes=pseudo-probe,sample-profile -sample-profile-file=%S/Inputs/pseudo-probe-profile.prof -pass-remarks=sample-profile -pass-remarks-output=%t.opt.yaml -sample-profile-use-profi=0 -S -o %t
+; RUN: FileCheck %s --input-file %t
+; RUN: FileCheck %s -check-prefix=YAML --input-file %t.opt.yaml
+; RUN: opt < %t -passes=sample-profile -sample-profile-file=%S/Inputs/pseudo-probe-profile.prof -sample-profile-remove-probe -S | FileCheck %s -check-prefix=REMOVE-PROBE
+
+; REMOVE-PROBE-NOT: call void @llvm.pseudoprobe
 
 define dso_local i32 @foo(i32 %x, ptr %f) #0 !dbg !4 {
 entry:

``````````

</details>


https://github.com/llvm/llvm-project/pull/90293