From eeca2b8bd03f57c59c6cf48bf6b9bd6dc86924f6 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 19 Apr 2022 18:58:59 +0200
Subject: [PATCH] sparc: Preserve ORIGINAL_REGNO in epilogue_renumber
 [PR105257]

The following testcase ICEs, because the pic register is
(reg:DI 24 %i0 [109]) and is used in the delay slot of a return.
We invoke epilogue_renumber and that changes it to
(reg:DI 8 %o0) which no longer satisfies sparc_pic_register_p
predicate, so we don't recognize the insn anymore.

The following patch fixes that by preserving ORIGINAL_REGNO if
specified, so we get (reg:DI 8 %o0 [109]) instead.

2022-04-19  Jakub Jelinek  <jakub@redhat.com>

	PR target/105257
	* config/sparc/sparc.cc (epilogue_renumber): If ORIGINAL_REGNO,
	use gen_raw_REG instead of gen_rtx_REG and copy over also
	ORIGINAL_REGNO.  Use return 0; instead of /* fallthrough */.

	* gcc.dg/pr105257.c: New test.
---
 gcc/config/sparc/sparc.cc       | 16 ++++++++++++++--
 gcc/testsuite/gcc.dg/pr105257.c | 16 ++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr105257.c

diff --git a/gcc/config/sparc/sparc.cc b/gcc/config/sparc/sparc.cc
index bb4ce88..467a9f1 100644
--- a/gcc/config/sparc/sparc.cc
+++ b/gcc/config/sparc/sparc.cc
@@ -8884,8 +8884,20 @@ epilogue_renumber (rtx *where, int test)
       if (REGNO (*where) >= 8 && REGNO (*where) < 24)      /* oX or lX */
 	return 1;
       if (! test && REGNO (*where) >= 24 && REGNO (*where) < 32)
-	*where = gen_rtx_REG (GET_MODE (*where), OUTGOING_REGNO (REGNO(*where)));
-      /* fallthrough */
+	{
+	  if (ORIGINAL_REGNO (*where))
+	    {
+	      rtx n = gen_raw_REG (GET_MODE (*where),
+				   OUTGOING_REGNO (REGNO (*where)));
+	      ORIGINAL_REGNO (n) = ORIGINAL_REGNO (*where);
+	      *where = n;
+	    }
+	  else
+	    *where = gen_rtx_REG (GET_MODE (*where),
+				  OUTGOING_REGNO (REGNO (*where)));
+	}
+      return 0;
+
     case SCRATCH:
     case PC:
     case CONST_INT:
diff --git a/gcc/testsuite/gcc.dg/pr105257.c b/gcc/testsuite/gcc.dg/pr105257.c
new file mode 100644
index 0000000..4232942
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr105257.c
@@ -0,0 +1,16 @@
+/* PR target/105257 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-additional-options "-fpic" { target fpic } } */
+
+extern int sigsetjmp (void **, int);
+void *buf[32];
+void (*fn) (void);
+
+const char *
+bar (void)
+{
+  sigsetjmp (buf, 0);
+  fn ();
+  return "";
+}
-- 
2.7.4