From: Richard Biener <rguenther@suse.de>
Date: Mon, 4 Oct 2021 12:24:07 +0000 (+0200)
Subject: avoid hardreg autoinit
X-Git-Tag: basepoints/gcc-13~4166
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d362b91fa655fb02a4214e28eb33b8b60a0e1ace;p=thirdparty%2Fgcc.git

avoid hardreg autoinit

This avoids initializating "uninitialized" hardregs like SP.

2021-10-04  Richard Biener  <rguenther@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.
---

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index f4bc649632ec..b27776af7c8a 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 000000000000..7c9de99bf056
--- /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;
+}