From ac868f29d7e81636b988cc4b67f681dce3498175 Mon Sep 17 00:00:00 2001
From: Eric Botcazou <ebotcazou@adacore.com>
Date: Wed, 11 Apr 2012 11:13:39 +0000
Subject: re PR target/52624 (missing __builtin_bswap16)

	PR target/52624
	* doc/extend.texi (Other Builtins): Document __builtin_bswap16.
	(PowerPC AltiVec/VSX Built-in Functions): Remove it.
	* doc/md.texi (Standard Names): Add bswap.
	* builtin-types.def (BT_UINT16): New primitive type.
	(BT_FN_UINT16_UINT16): New function type.
	* builtins.def (BUILT_IN_BSWAP16): New.
	* builtins.c (expand_builtin_bswap): Add TARGET_MODE argument.
	(expand_builtin) <BUILT_IN_BSWAP16>: New case.  Pass TARGET_MODE to
	expand_builtin_bswap.
	(fold_builtin_bswap): Add BUILT_IN_BSWAP16 case.
	(fold_builtin_1): Likewise.
	(is_inexpensive_builtin): Likewise.
	* optabs.c (expand_unop): Deal with bswap in HImode specially.  Add
	missing bits for bswap to libcall code.
	* tree.c (build_common_tree_nodes): Build uint16_type_node.
	* tree.h (enum tree_index): Add TI_UINT16_TYPE.
	(uint16_type_node): New define.
	* config/rs6000/rs6000-builtin.def (RS6000_BUILTIN_BSWAP_HI): Delete.
	* config/rs6000/rs6000.c (rs6000_expand_builtin): Remove handling of
	above builtin.
	(rs6000_init_builtins): Likewise.
	* config/rs6000/rs6000.md (bswaphi2): Add TARGET_POWERPC predicate.
c-family/
	* c-common.h (uint16_type_node): Rename into...
	(c_uint16_type_node): ...this.
	* c-common.c (c_common_nodes_and_builtins): Adjust for above renaming.
	* c-cppbuiltin.c (builtin_define_stdint_macros): Likewise.

From-SVN: r186308
---
 gcc/optabs.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 57 insertions(+), 2 deletions(-)

(limited to 'gcc/optabs.c')

diff --git a/gcc/optabs.c b/gcc/optabs.c
index 565db42..080061a 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -3030,6 +3030,47 @@ expand_unop (enum machine_mode mode, optab unoptab, rtx op0, rtx target,
   /* Widening (or narrowing) bswap needs special treatment.  */
   if (unoptab == bswap_optab)
     {
+      /* HImode is special because in this mode BSWAP is equivalent to ROTATE
+	 or ROTATERT.  First try these directly; if this fails, then try the
+	 obvious pair of shifts with allowed widening, as this will probably
+	 be always more efficient than the other fallback methods.  */
+      if (mode == HImode)
+	{
+	  rtx last, temp1, temp2;
+
+	  if (optab_handler (rotl_optab, mode) != CODE_FOR_nothing)
+	    {
+	      temp = expand_binop (mode, rotl_optab, op0, GEN_INT (8), target,
+				   unsignedp, OPTAB_DIRECT);
+	      if (temp)
+		return temp;
+	     }
+
+	  if (optab_handler (rotr_optab, mode) != CODE_FOR_nothing)
+	    {
+	      temp = expand_binop (mode, rotr_optab, op0, GEN_INT (8), target,
+				   unsignedp, OPTAB_DIRECT);
+	      if (temp)
+		return temp;
+	    }
+
+	  last = get_last_insn ();
+
+	  temp1 = expand_binop (mode, ashl_optab, op0, GEN_INT (8), NULL_RTX,
+			        unsignedp, OPTAB_WIDEN);
+	  temp2 = expand_binop (mode, lshr_optab, op0, GEN_INT (8), NULL_RTX,
+			        unsignedp, OPTAB_WIDEN);
+	  if (temp1 && temp2)
+	    {
+	      temp = expand_binop (mode, ior_optab, temp1, temp2, target,
+				   unsignedp, OPTAB_WIDEN);
+	      if (temp)
+		return temp;
+	    }
+
+	  delete_insns_since (last);
+	}
+
       temp = widen_bswap (mode, op0, target);
       if (temp)
 	return temp;
@@ -3222,10 +3263,10 @@ expand_unop (enum machine_mode mode, optab unoptab, rtx op0, rtx target,
 	      /* For certain operations, we need not actually extend
 		 the narrow operand, as long as we will truncate the
 		 results to the same narrowness.  */
-
 	      xop0 = widen_operand (xop0, wider_mode, mode, unsignedp,
 				    (unoptab == neg_optab
-				     || unoptab == one_cmpl_optab)
+				     || unoptab == one_cmpl_optab
+				     || unoptab == bswap_optab)
 				    && mclass == MODE_INT);
 
 	      temp = expand_unop (wider_mode, unoptab, xop0, NULL_RTX,
@@ -3240,6 +3281,20 @@ expand_unop (enum machine_mode mode, optab unoptab, rtx op0, rtx target,
 					      - GET_MODE_PRECISION (mode)),
 				     target, true, OPTAB_DIRECT);
 
+	      /* Likewise for bswap.  */
+	      if (unoptab == bswap_optab && temp != 0)
+		{
+		  gcc_assert (GET_MODE_PRECISION (wider_mode)
+			      == GET_MODE_BITSIZE (wider_mode)
+			      && GET_MODE_PRECISION (mode)
+				 == GET_MODE_BITSIZE (mode));
+
+		  temp = expand_shift (RSHIFT_EXPR, wider_mode, temp,
+				       GET_MODE_BITSIZE (wider_mode)
+				       - GET_MODE_BITSIZE (mode),
+				       NULL_RTX, true);
+		}
+
 	      if (temp)
 		{
 		  if (mclass != MODE_INT)
-- 
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