[llvm] fix cratch in tail call return type (PR #210579)

[via llvm-commits]

https://github.com/SomeFlyingThing updated https://github.com/llvm/llvm-project/pull/210579

>From 920ead400a04fa5257993815d23360d442b7de4c Mon Sep 17 00:00:00 2001
From: SomeFlyingThing <306498559+SomeFlyingThing at users.noreply.github.com>
Date: Sun, 19 Jul 2026 08:52:10 +0100
Subject: [PATCH] fix cratch in tail call return type

---
 llvm/lib/CodeGen/Analysis.cpp                      | 6 ++++--
 llvm/test/CodeGen/X86/tail-call-empty-aggregate.ll | 9 +++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/CodeGen/X86/tail-call-empty-aggregate.ll

diff --git a/llvm/lib/CodeGen/Analysis.cpp b/llvm/lib/CodeGen/Analysis.cpp
index 9ece9f0c187a2..c4d50b38479a5 100644
--- a/llvm/lib/CodeGen/Analysis.cpp
+++ b/llvm/lib/CodeGen/Analysis.cpp
@@ -692,8 +692,10 @@ bool llvm::returnTypeIsEligibleForTailCall(const Function *F,
       // We've exhausted the values produced by the tail call instruction, the
       // rest are essentially undef. The type doesn't really matter, but we need
       // *something*.
-      Type *SlotType =
-          ExtractValueInst::getIndexedType(RetSubTypes.back(), RetPath.back());
+      Type *SlotType = RetVal->getType();
+      if (!RetPath.empty())
+        SlotType = ExtractValueInst::getIndexedType(RetSubTypes.back(),
+                                                    RetPath.back());
       CallVal = UndefValue::get(SlotType);
     }
 
diff --git a/llvm/test/CodeGen/X86/tail-call-empty-aggregate.ll b/llvm/test/CodeGen/X86/tail-call-empty-aggregate.ll
new file mode 100644
index 0000000000000..1b2e86af6f79b
--- /dev/null
+++ b/llvm/test/CodeGen/X86/tail-call-empty-aggregate.ll
@@ -0,0 +1,9 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -o /dev/null
+
+declare { {} } @callee()
+
+define i32 @caller() {
+entry:
+  %call = tail call { {} } @callee()
+  ret i32 0
+}