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-rw-r--r--include/qemu/compiler.h11
-rw-r--r--tcg/optimize.c4
2 files changed, 15 insertions, 0 deletions
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index 1b9e58e82b..df9ec08f8a 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -222,4 +222,15 @@ extern void QEMU_NORETURN QEMU_ERROR("code path is reachable")
#define qemu_build_not_reached() g_assert_not_reached()
#endif
+/**
+ * In most cases, normal "fallthrough" comments are good enough for
+ * switch-case statements, but sometimes the compiler has problems
+ * with those. In that case you can use QEMU_FALLTHROUGH instead.
+ */
+#if __has_attribute(fallthrough)
+# define QEMU_FALLTHROUGH __attribute__((fallthrough))
+#else
+# define QEMU_FALLTHROUGH do {} while (0) /* fallthrough */
+#endif
+
#endif /* COMPILER_H */
diff --git a/tcg/optimize.c b/tcg/optimize.c
index 220f4601d5..7ca71de956 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -855,6 +855,7 @@ void tcg_optimize(TCGContext *s)
if ((arg_info(op->args[1])->mask & 0x80) != 0) {
break;
}
+ QEMU_FALLTHROUGH;
CASE_OP_32_64(ext8u):
mask = 0xff;
goto and_const;
@@ -862,6 +863,7 @@ void tcg_optimize(TCGContext *s)
if ((arg_info(op->args[1])->mask & 0x8000) != 0) {
break;
}
+ QEMU_FALLTHROUGH;
CASE_OP_32_64(ext16u):
mask = 0xffff;
goto and_const;
@@ -869,6 +871,7 @@ void tcg_optimize(TCGContext *s)
if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
break;
}
+ QEMU_FALLTHROUGH;
case INDEX_op_ext32u_i64:
mask = 0xffffffffU;
goto and_const;
@@ -886,6 +889,7 @@ void tcg_optimize(TCGContext *s)
if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
break;
}
+ QEMU_FALLTHROUGH;
case INDEX_op_extu_i32_i64:
/* We do not compute affected as it is a size changing op. */
mask = (uint32_t)arg_info(op->args[1])->mask;