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.

diff --git a/gcc/config/sparc/sparc.cc b/gcc/config/sparc/sparc.cc
index bb4ce88..467a9f1 100644 (file)
--- 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 (file)
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 "";
+}