Index: test/backtrace_test.sh.cpp
===================================================================
--- test/backtrace_test.sh.cpp
+++ test/backtrace_test.sh.cpp
@@ -9,6 +9,11 @@
 
 // UNSUPPORTED: libcxxabi-no-exceptions
 
+// We're comparing frame counts, so suppress inlining and tail call elimination
+// to avoid mismatches caused by optimizations.
+// RUN: %build -fno-inline -fno-optimize-sibling-calls
+// RUN: %run
+
 #include <assert.h>
 #include <stddef.h>
 #include <unwind.h>