Avoid unaligned loads in jit_lvn_copy

nickg · Aug 6, 2023 · ea12e4a · ea12e4a
1 parent e333b87
commit ea12e4a
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/src/jit/jit-optim.c b/src/jit/jit-optim.c
@@ -777,15 +777,15 @@ static void jit_lvn_copy(jit_ir_t *ir, lvn_state_t *state)
          switch (count) {
          case 8:
             ir->size = JIT_SZ_64;
-            ir->arg1 = LVN_CONST(*(uint64_t *)src);
+            ir->arg1 = LVN_CONST(unaligned_load(src, uint64_t));
             break;
          case 4:
             ir->size = JIT_SZ_32;
-            ir->arg1 = LVN_CONST(*(uint32_t *)src);
+            ir->arg1 = LVN_CONST(unaligned_load(src, uint32_t));
             break;
          case 2:
             ir->size = JIT_SZ_16;
-            ir->arg1 = LVN_CONST(*(uint16_t *)src);
+            ir->arg1 = LVN_CONST(unaligned_load(src, uint16_t));
             break;
          case 1:
             ir->size = JIT_SZ_8;

diff --git a/src/util.h b/src/util.h
@@ -451,4 +451,10 @@ void list_clear(ptr_list_t *l);
 #define PACK_BE64(u) \
    PACK_BE32(u >> 32), PACK_BE32(u)
 
+#define unaligned_load(ptr, type) ({                                    \
+         const struct { type value; }                                   \
+            __attribute__((packed)) *s = ptr;                           \
+         s->value;                                                      \
+      })
+
 #endif // _UTIL_H