function.c (purge_addressof_1): In (mem (addressof (reg))) case for reg notes...

	* function.c (purge_addressof_1): In (mem (addressof (reg))) case
	for reg notes, if there are no substitutions, just use a SUBREG.

From-SVN: r65934

1 files changed, 30 insertions, 0 deletions

diff --git a/gcc/function.c b/gcc/function.c
index b75a07e..de10f73 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -3147,6 +3147,36 @@ purge_addressof_1 (loc, insn, force, store, may_postpone, ht)
 		    return true;
 		  }
 
+	      /* When we are processing the REG_NOTES of the last instruction
+		 of a libcall, there will be typically no replacements
+		 for that insn; the replacements happened before, piecemeal
+		 fashion.  OTOH we are not interested in the details of
+		 this for the REG_EQUAL note, we want to know the big picture,
+		 which can be succinctly described with a simple SUBREG.
+		 Note that removing the REG_EQUAL note is not an option
+		 on the last insn of a libcall, so we must do a replacement.  */
+	      if (! purge_addressof_replacements
+		  && ! purge_bitfield_addressof_replacements)
+		{
+		  /* In compile/990107-1.c:7 compiled at -O1 -m1 for sh-elf,
+		     we got
+		     (mem:DI (addressof:SI (reg/v:DF 160) 159 0x401c8510)
+		      [0 S8 A32]), which can be expressed with a simple
+		     same-size subreg  */
+		  if ((GET_MODE_SIZE (GET_MODE (x))
+		       == GET_MODE_SIZE (GET_MODE (sub)))
+		      /* Again, invalid pointer casts (as in
+			 compile/990203-1.c) can require paradoxical
+			 subregs.  */
+		      || (GET_MODE_SIZE (GET_MODE (x)) > UNITS_PER_WORD
+			  && (GET_MODE_SIZE (GET_MODE (x))
+			      > GET_MODE_SIZE (GET_MODE (sub)))))
+		    {
+		      *loc = gen_rtx_SUBREG (GET_MODE (x), sub, 0);
+		      return true;
+		    }
+		  /* ??? Are there other cases we should handle?  */
+		}
 	      /* Sometimes we may not be able to find the replacement.  For
 		 example when the original insn was a MEM in a wider mode,
 		 and the note is part of a sign extension of a narrowed