re PR target/16458 (PowerPC - redundant compare)

gcc/
	PR target/16458
	* rtlanal.c (unsigned_reg_p): New function.
	Update copyright notice dates.
	* rtl.h (unsigned_reg_p): Prototype it.
	Update copyright notice dates.
	* config/rs6000/rs6000.c (rs6000_generate_compare): Use it.
	Update comment.
	* expr.c (expand_expr_real_1): Set register attributes.
	* stmt.c (expand_case): Likewise.

gcc/testsuite/
	PR target/16458
	* gcc.target/powerpc/pr16458-1.c: New test.
	* gcc.target/powerpc/pr16458-2.c: Likewise.
	* gcc.target/powerpc/pr16458-3.c: Likewise.
	* gcc.target/powerpc/pr16458-4.c: Likewise.

Co-Authored-By: Michael Matz <matz@suse.de>

From-SVN: r186312

1 files changed, 7 insertions, 2 deletions

diff --git a/gcc/expr.c b/gcc/expr.c
index 548a407..14709bf 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -9015,8 +9015,13 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
 	  && stmt_is_replaceable_p (SSA_NAME_DEF_STMT (exp)))
 	g = SSA_NAME_DEF_STMT (exp);
       if (g)
-	return expand_expr_real (gimple_assign_rhs_to_tree (g), target, tmode,
-				 modifier, NULL);
+	{
+	  rtx r = expand_expr_real (gimple_assign_rhs_to_tree (g), target,
+				    tmode, modifier, NULL);
+	  if (REG_P (r) && !REG_EXPR (r))
+	    set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (exp), r);
+	  return r;
+	}
 
       ssa_name = exp;
       decl_rtl = get_rtx_for_ssa_name (ssa_name);