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From: "vmakarov at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/104117] [9,10,11,12 Regression] Darwin ppc64 uses
 invalid non-PIC address to access constants (in PIC code).
Date: Fri, 04 Feb 2022 22:05:27 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104117

--- Comment #13 from Vladimir Makarov <vmakarov at gcc dot gnu.org> ---
I think there are two code spots whose pitfalls resulted in the PR.

The first one is in rs6000.cc::legitimate_lo_sum_address_p which permits wr=
ong
pic low-sum address.

Another one is in lra-constraints.cc::process_address_1 which permits put w=
rong
low-sum address in reg and use the reg in memory.

The following patch solves the problem:

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 5404fb18755..306f67f26c4 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -8202,7 +8202,7 @@ legitimate_lo_sum_address_p (machine_mode mode, rtx x,
int strict)
     {
       bool large_toc_ok;

-      if (DEFAULT_ABI =3D=3D ABI_V4 && flag_pic)
+      if ((DEFAULT_ABI =3D=3D ABI_V4 || DEFAULT_ABI =3D=3D ABI_DARWIN) && =
flag_pic)
        return false;
       /* LRA doesn't use LEGITIMIZE_RELOAD_ADDRESS as it usually calls
         push_reload from reload pass code.  LEGITIMIZE_RELOAD_ADDRESS
diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 30d088afbca..998e82be54f 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -3517,21 +3517,8 @@ process_address_1 (int nop, bool check_only_p,
                  *ad.inner =3D gen_rtx_LO_SUM (Pmode, new_reg, addr);
                  if (!valid_address_p (op, &ad, cn))
                    {
-                     /* Try to put lo_sum into register.  */
-                     insn =3D emit_insn (gen_rtx_SET
-                                       (new_reg,
-                                        gen_rtx_LO_SUM (Pmode, new_reg,
addr)));
-                     code =3D recog_memoized (insn);
-                     if (code >=3D 0)
-                       {
-                         *ad.inner =3D new_reg;
-                         if (!valid_address_p (op, &ad, cn))
-                           {
-                             *ad.inner =3D addr;
-                             code =3D -1;
-                           }
-                       }
-
+                     *ad.inner =3D addr;
+                     code =3D -1;
                    }
                }
              if (code < 0)

The patch was successfully tested on x86-64/ppc64 under Linux.=