From afdca0e780760e008e26f4c9fc7262a0a4fe56bb Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Tue, 26 Oct 2021 20:14:19 +0900
Subject: [PATCH] Fix unaligned access to `double` in RFloat

---
 internal/numeric.h | 12 ++++++++++++
 numeric.c          |  4 ++++
 2 files changed, 16 insertions(+)

diff --git a/internal/numeric.h b/internal/numeric.h
index 6bb7baf204..3d88845a16 100644
--- a/internal/numeric.h
+++ b/internal/numeric.h
@@ -206,10 +206,22 @@ rb_float_flonum_value(VALUE v)
     return 0.0;
 }
 
+#if SIZEOF_VALUE >= SIZEOF_DOUBLE || defined(UNALIGNED_WORD_ACCESS)
+# define UNALIGNED_DOUBLE_ACCESS 1
+#else
+# define UNALIGNED_DOUBLE_ACCESS 0
+#endif
+
 static inline double
 rb_float_noflonum_value(VALUE v)
 {
+#if UNALIGNED_DOUBLE_ACCESS
     return RFLOAT(v)->float_value;
+#else
+    double d;
+    memcpy(&d, &RFLOAT(v)->float_value, sizeof(double));
+    return d;
+#endif
 }
 
 static inline double
diff --git a/numeric.c b/numeric.c
index d216240520..e12bcce5b8 100644
--- a/numeric.c
+++ b/numeric.c
@@ -951,7 +951,11 @@ rb_float_new_in_heap(double d)
 {
     NEWOBJ_OF(flt, struct RFloat, rb_cFloat, T_FLOAT | (RGENGC_WB_PROTECTED_FLOAT ? FL_WB_PROTECTED : 0));
 
+#if UNALIGNED_DOUBLE_ACCESS
     flt->float_value = d;
+#else
+    memcpy(&flt->float_value, &d, sizeof(double));
+#endif
     OBJ_FREEZE((VALUE)flt);
     return (VALUE)flt;
 }