[llvm] [InstrProf] Do not block functions from PGOUse (PR #71106)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-pgo

Author: Ellis Hoag (ellishg)

<details>
<summary>Changes</summary>

The `skipPGO()` function was added in https://reviews.llvm.org/D137184. Unfortunately, it also blocked functions from being annotated (PGOUse), which I believe will cause confusion to users if a function has a profile but it is not PGO'd.

The docs for `noprofile` and `skipprofile` only claim to block instrumentation, not PGO optimization: https://llvm.org/docs/LangRef.html

---
Full diff: https://github.com/llvm/llvm-project/pull/71106.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp (+2-2) 


``````````diff
diff --git a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
index 7ad1c9bc54f3780..1474ccc2b978fd8 100644
--- a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -1760,7 +1760,7 @@ static void collectComdatMembers(
       ComdatMembers.insert(std::make_pair(C, &GA));
 }
 
-// Don't perform PGO instrumeatnion / profile-use.
+// Return true if we should skip instrumenting this function
 static bool skipPGO(const Function &F) {
   if (F.isDeclaration())
     return true;
@@ -2031,7 +2031,7 @@ static bool annotateAllFunctions(
     InstrumentFuncEntry = PGOInstrumentEntry;
   bool HasSingleByteCoverage = PGOReader->hasSingleByteCoverage();
   for (auto &F : M) {
-    if (skipPGO(F))
+    if (F.isDeclaration())
       continue;
     auto &TLI = LookupTLI(F);
     auto *BPI = LookupBPI(F);

``````````

</details>


https://github.com/llvm/llvm-project/pull/71106