diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
@@ -132,6 +132,12 @@
 # define SANITIZER_X32 0
 #endif
 
+#if defined(__i386__) || defined(_M_IX86)
+# define SANITIZER_I386 1
+#else
+# define SANITIZER_I386 0
+#endif
+
 #if defined(__mips__)
 # define SANITIZER_MIPS 1
 # if defined(__mips64)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -597,7 +597,10 @@
 #define SANITIZER_INTERCEPT_QSORT \
   (SI_POSIX && !SI_IOSSIM && !SI_WATCHOS && !SI_TVOS && !SI_ANDROID)
 #define SANITIZER_INTERCEPT_QSORT_R (SI_LINUX && !SI_ANDROID)
-#define SANITIZER_INTERCEPT_SIGALTSTACK SI_POSIX
+// sigaltstack on i386 macOS cannot be intercepted due to setjmp()
+// calling it and assuming that it does not clobber registers.
+#define SANITIZER_INTERCEPT_SIGALTSTACK \
+  (SI_POSIX && !(SANITIZER_MAC && SANITIZER_I386))
 #define SANITIZER_INTERCEPT_UNAME (SI_POSIX && !SI_FREEBSD)
 #define SANITIZER_INTERCEPT___XUNAME SI_FREEBSD