AVR: target/64242 - Copy FP to a local reg in nonlocal_goto.

In nonlocal_goto sets, change hard_frame_pointer_rtx only after
emit_stack_restore() restored SP.  This is needed because SP
my be stored in some frame location.

gcc/
	PR target/64242
	* config/avr/avr.md (nonlocal_goto): Don't restore
	hard_frame_pointer_rtx directly, but copy it to local
	register, and only set hard_frame_pointer_rtx from it
	after emit_stack_restore().

(cherry picked from commit f7b5527d1b48b33d8ab633c1e9dcb9883667492a)

diff --git a/gcc/config/avr/avr.md b/gcc/config/avr/avr.md
index f76249340b8fb23367fbacf6b592c2d201b360e7..90ba2d0400e4b0860d51abceeed837a4f7116b11 100644 (file)
--- a/gcc/config/avr/avr.md
+++ b/gcc/config/avr/avr.md
@@ -381,9 +381,14 @@
 
     emit_clobber (gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx));
 
-    emit_move_insn (hard_frame_pointer_rtx, r_fp);
+    // PR64242: When r_sp is located in the frame, we must not
+    // change FP prior to reading r_sp.  Hence copy r_fp to a
+    // local register (and hope that reload won't spill it).
+    rtx r_fp_reg = copy_to_reg (r_fp);
     emit_stack_restore (SAVE_NONLOCAL, r_sp);
 
+    emit_move_insn (hard_frame_pointer_rtx, r_fp_reg);
+
     emit_use (hard_frame_pointer_rtx);
     emit_use (stack_pointer_rtx);