[nvptx] Split up function ref plus const

With test-case gcc.c-torture/compile/pr92231.c, we run into:
...
nvptx-as: ptxas terminated with signal 11 [Segmentation fault], core dumped^M
compiler exited with status 1
FAIL: gcc.c-torture/compile/pr92231.c   -O0  (test for excess errors)
...
due to using a function reference plus constant as operand:
...
  mov.u64 %r24,bar+4096';
...

Fix this by splitting such an insn into:
...
  mov.u64 %r24,bar';
  add.u64 %r24,%r24,4096';
...

Tested on nvptx.

gcc/ChangeLog:

	* config/nvptx/nvptx.md: Don't allow operand containing sum of
	function ref and const.

gcc/config/nvptx/nvptx.md

@@ -146,6 +146,13 @@
   return true;
 })
 
+;; Test for a function symbol ref operand
+(define_predicate "symbol_ref_function_operand"
+  (match_code "symbol_ref")
+{
+  return SYMBOL_REF_FUNCTION_P (op);
+})
+
 (define_attr "predicable" "false,true"
   (const_string "true"))
 
@@ -241,6 +248,17 @@
 }
   [(set_attr "subregs_ok" "true")])
 
+;; ptxas segfaults on 'mov.u64 %r24,bar+4096', so break it up.
+(define_split
+  [(set (match_operand:DI 0 "nvptx_register_operand")
+	(const:DI (plus:DI (match_operand:DI 1 "symbol_ref_function_operand")
+			   (match_operand 2 "const_int_operand"))))]
+  ""
+  [(set (match_dup 0) (match_dup 1))
+   (set (match_dup 0) (plus:DI (match_dup 0) (match_dup 2)))
+  ]
+  "")
+
 (define_insn "*mov<mode>_insn"
   [(set (match_operand:SDFM 0 "nonimmediate_operand" "=R,R,m")
 	(match_operand:SDFM 1 "general_operand" "RF,m,R"))]