[llvm] PlaceSafepoints: Fix using default constructed TargetLibraryInfo (PR #92411)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>

PlaceSafepoints has an awful hack where it's creating a legacy
PassManager inside it's runImpl, which was not propagating the incoming
TLI. This means there's an implicit bug fix, where PlaceSafepoints would have
 been treating too many calls as builtins.

Split from #<!-- -->92400 

---
Full diff: https://github.com/llvm/llvm-project/pull/92411.diff


4 Files Affected:

- (modified) llvm/include/llvm/Analysis/TargetLibraryInfo.h (+4) 
- (modified) llvm/lib/Analysis/TargetLibraryInfo.cpp (+4) 
- (modified) llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp (+2) 
- (modified) llvm/test/Transforms/PlaceSafepoints/libcall.ll (+5-2) 


``````````diff
diff --git a/llvm/include/llvm/Analysis/TargetLibraryInfo.h b/llvm/include/llvm/Analysis/TargetLibraryInfo.h
index 46f31f918e7b6..f5da222d11f55 100644
--- a/llvm/include/llvm/Analysis/TargetLibraryInfo.h
+++ b/llvm/include/llvm/Analysis/TargetLibraryInfo.h
@@ -633,6 +633,10 @@ class TargetLibraryInfoWrapperPass : public ImmutablePass {
   explicit TargetLibraryInfoWrapperPass(const Triple &T);
   explicit TargetLibraryInfoWrapperPass(const TargetLibraryInfoImpl &TLI);
 
+  // FIXME: This should be removed when PlaceSafepoints is fixed to not create a
+  // PassManager inside a pass.
+  explicit TargetLibraryInfoWrapperPass(const TargetLibraryInfo &TLI);
+
   TargetLibraryInfo &getTLI(const Function &F) {
     FunctionAnalysisManager DummyFAM;
     TLI = TLA.run(F, DummyFAM);
diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index c62d9daa13ef0..684b0759f3157 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -1383,6 +1383,10 @@ TargetLibraryInfoWrapperPass::TargetLibraryInfoWrapperPass(
   initializeTargetLibraryInfoWrapperPassPass(*PassRegistry::getPassRegistry());
 }
 
+TargetLibraryInfoWrapperPass::TargetLibraryInfoWrapperPass(
+    const TargetLibraryInfo &TLIOther)
+    : TargetLibraryInfoWrapperPass(*TLIOther.Impl) {}
+
 AnalysisKey TargetLibraryAnalysis::Key;
 
 // Register the basic pass.
diff --git a/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp b/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp
index 77d155d7e78e3..dcdea6e7b62ae 100644
--- a/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp
+++ b/llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp
@@ -288,6 +288,8 @@ bool PlaceSafepointsPass::runImpl(Function &F, const TargetLibraryInfo &TLI) {
     // with for the moment.
     legacy::FunctionPassManager FPM(F.getParent());
     bool CanAssumeCallSafepoints = enableCallSafepoints(F);
+
+    FPM.add(new TargetLibraryInfoWrapperPass(TLI));
     auto *PBS = new PlaceBackedgeSafepointsLegacyPass(CanAssumeCallSafepoints);
     FPM.add(PBS);
     FPM.run(F);
diff --git a/llvm/test/Transforms/PlaceSafepoints/libcall.ll b/llvm/test/Transforms/PlaceSafepoints/libcall.ll
index 89090ba1b243c..6e26f924a5ba3 100644
--- a/llvm/test/Transforms/PlaceSafepoints/libcall.ll
+++ b/llvm/test/Transforms/PlaceSafepoints/libcall.ll
@@ -1,4 +1,6 @@
-; RUN: opt -S -passes=place-safepoints < %s | FileCheck %s
+; RUN: opt -S -passes=place-safepoints < %s | FileCheck -check-prefixes=CHECK,WITHLDEXPF %s
+; RUN: opt -S -passes=place-safepoints -disable-builtin=ldexp < %s | FileCheck %s
+
 
 ; Libcalls will not contain a safepoint poll, so check that we insert
 ; a safepoint in a loop containing a libcall.
@@ -17,7 +19,8 @@ loop:
 ; CHECK-NEXT: %x_loop = phi double [ %x, %entry ], [ %x_exp, %loop ]
 ; CHECK-NEXT: %x_exp = call double @ldexp(double %x_loop, i32 5)
 ; CHECK-NEXT: %done = fcmp ogt double %x_exp, 1.5
-; CHECK-NEXT: call void @do_safepoint
+; WITHLDEXPF-NEXT: call void @do_safepoint
+; CHECK-NEXT: br
   %x_loop = phi double [ %x, %entry ], [ %x_exp, %loop ]
   %x_exp = call double @ldexp(double %x_loop, i32 5) nounwind readnone
   %done = fcmp ogt double %x_exp, 1.5

``````````

</details>


https://github.com/llvm/llvm-project/pull/92411