[llvm] [GlobalOpt] Fix unreachable ifunc globalopt crash (#157332) (PR #157593)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Justin Riddell (Arghnews)

<details>
<summary>Changes</summary>

Also fixes (#<!-- -->131488)

Unreachable case is triggering `Callees.empty()` assert. Since this was [originally ](https://github.com/llvm/llvm-project/pull/87939/commits/02bd5a7013c558f1e5220fc89bafa68f40276549#diff-06aba0dac2a263dc14297a15655291d5506b760f54a736385bcf3208f83df843R2524) a `continue` anyway, have applied that as a fix and added a test case

---
Full diff: https://github.com/llvm/llvm-project/pull/157593.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/IPO/GlobalOpt.cpp (+2-1) 
- (added) llvm/test/Transforms/GlobalOpt/resolve-indirect-ifunc.ll (+11) 


``````````diff
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index d7edd1288309b..f88d51f443bcf 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2551,7 +2551,8 @@ static bool OptimizeNonTrivialIFuncs(
         }))
       continue;
 
-    assert(!Callees.empty() && "Expecting successful collection of versions");
+    if (Callees.empty())
+      continue;
 
     LLVM_DEBUG(dbgs() << "Statically resolving calls to function "
                       << Resolver->getName() << "\n");
diff --git a/llvm/test/Transforms/GlobalOpt/resolve-indirect-ifunc.ll b/llvm/test/Transforms/GlobalOpt/resolve-indirect-ifunc.ll
new file mode 100644
index 0000000000000..1f944a7bde19b
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/resolve-indirect-ifunc.ll
@@ -0,0 +1,11 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt --passes=globalopt -o - -S < %s | FileCheck %s
+
+define ptr @f1() partition "part1" {
+; CHECK-LABEL: define ptr @f1() partition "part1" {
+; CHECK-NEXT:    unreachable
+;
+  unreachable
+}
+
+ at i1 = ifunc void(), ptr @f1, partition "part2"

``````````

</details>


https://github.com/llvm/llvm-project/pull/157593