This avoids initializating "uninitialized" hardregs like SP.
Bootstrap / regtest pending on x86_64-unknown-linux-gnu.
2021-10-04 Richard Biener <rguent...@suse.de>
* gimplify.c (is_var_need_auto_init): DECL_HARD_REGISTER
variables are not to be initialized.
* gcc.dg/auto-init-hardreg-1.c: New testcase.
---
gcc/gimplify.c | 2 ++
gcc/testsuite/gcc.dg/auto-init-hardreg-1.c | 9 +++++++++
2 files changed, 11 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/auto-init-hardreg-1.c
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index f4bc649632e..b27776af7c8 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -1825,6 +1825,8 @@ static bool
is_var_need_auto_init (tree decl)
{
if (auto_var_p (decl)
+ && (TREE_CODE (decl) != VAR_DECL
+ || !DECL_HARD_REGISTER (decl))
&& (flag_auto_var_init > AUTO_INIT_UNINITIALIZED)
&& (!lookup_attribute ("uninitialized", DECL_ATTRIBUTES (decl)))
&& !is_empty_type (TREE_TYPE (decl)))
diff --git a/gcc/testsuite/gcc.dg/auto-init-hardreg-1.c
b/gcc/testsuite/gcc.dg/auto-init-hardreg-1.c
new file mode 100644
index 00000000000..7c9de99bf05
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/auto-init-hardreg-1.c
@@ -0,0 +1,9 @@
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-ftrivial-auto-var-init=zero" } */
+
+int
+main ()
+{
+ register long *sp __asm__("sp");
+ return 0;
+}
--
2.31.1
