[SimplifyCFG] Refine metadata handling during instruction hoisting

[wsmoses]

No description provided.

[llvmbot]

@llvm/pr-subscribers-debuginfo

@llvm/pr-subscribers-llvm-transforms

Author: William Moses (wsmoses)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/158448.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Utils/SimplifyCFG.cpp (+4-2)

diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 5a842f9b49c1b..6d6e32d51b62e 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -3387,11 +3387,13 @@ bool SimplifyCFGOpt::speculativelyExecuteBB(BranchInst *BI,
   // Metadata can be dependent on the condition we are hoisting above.
   // Strip all UB-implying metadata on the instruction. Drop the debug loc
   // to avoid making it appear as if the condition is a constant, which would
-  // be misleading while debugging.
+  // be misleading while debugging. However, make sure to keep debug info
+  // for calls as inlinable function calls in a function with debug info must
+  // have a !dbg location.
   // Similarly strip attributes that maybe dependent on condition we are
   // hoisting above.
   for (auto &I : make_early_inc_range(*ThenBB)) {
-    if (!SpeculatedStoreValue || &I != SpeculatedStore) {
+    if (!SpeculatedStoreValue || &I != SpeculatedStore && !isa<CallBase>(&I)) {
       I.setDebugLoc(DebugLoc::getDropped());
     }
     I.dropUBImplyingAttrsAndMetadata();

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[fhahn]

Could you add a test?

[wsmoses]

Yeah, though I'm a bit unsure how to set one up for this part of the pass

[wsmoses]

@fhahn okay figured it out, can you give it a review?

[nikic]

LGTM