[gcc(refs/users/guojiufu/heads/personal-branch)] Add processing STRICT_LOW_PART for matched reloads.

[gcc(refs/users/guojiufu/heads/personal-branch)] Add processing STRICT_LOW_PART for matched reloads.

[Jiu Fu Guo]

https://gcc.gnu.org/g:5261cf8ce824bfc75eb6f12ad5e3716c085b6f9a

commit 5261cf8ce824bfc75eb6f12ad5e3716c085b6f9a
Author: Vladimir N. Makarov <vmakarov@redhat.com>
Date:   Thu Jun 4 12:04:48 2020 -0400

    Add processing STRICT_LOW_PART for matched reloads.
    
    2020-06-04  Vladimir Makarov  <vmakarov@redhat.com>
    
            PR middle-end/95464
            * lra.c (lra_emit_move): Add processing STRICT_LOW_PART.
            * lra-constraints.c (match_reload): Use STRICT_LOW_PART in output
            reload if the original insn has it too.

Diff:
---
 gcc/lra-constraints.c | 2 ++
 gcc/lra.c             | 7 +++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index bf6d4a2fd4b..421c453997b 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -1071,6 +1071,8 @@ match_reload (signed char out, signed char *ins, signed char *outs,
   if (find_reg_note (curr_insn, REG_UNUSED, out_rtx) == NULL_RTX)
     {
       start_sequence ();
+      if (out >= 0 && curr_static_id->operand[out].strict_low)
+	out_rtx = gen_rtx_STRICT_LOW_PART (VOIDmode, out_rtx);
       lra_emit_move (out_rtx, copy_rtx (new_out_reg));
       emit_insn (*after);
       *after = get_insns ();
diff --git a/gcc/lra.c b/gcc/lra.c
index 3435cff6a1d..caa09d86ca6 100644
--- a/gcc/lra.c
+++ b/gcc/lra.c
@@ -490,13 +490,16 @@ void
 lra_emit_move (rtx x, rtx y)
 {
   int old;
-
+  rtx_insn *insn;
+  
   if (GET_CODE (y) != PLUS)
     {
       if (rtx_equal_p (x, y))
 	return;
       old = max_reg_num ();
-      rtx_insn *insn = emit_move_insn (x, y);
+
+      insn = (GET_CODE (x) != STRICT_LOW_PART
+	      ? emit_move_insn (x, y) : emit_insn (gen_rtx_SET (x, y)));
       /* The move pattern may require scratch registers, so convert them
 	 into real registers now.  */
       if (insn != NULL_RTX)