[PATCH 02/13] optabs: Fix vec_perm -> V16QI middle end lowering.

[Andreas Krebbel]

The current implementation re-uses the location of the selection
pattern to generate a new one.  This fails if the pattern resides in a
read-only location.  With the patch a new temporary register is
allocated for that purpose.

gcc/
	* optabs.c (expand_vec_perm): Allocate a temp reg for the new
          select pattern.
---
 gcc/optabs.c |   18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/gcc/optabs.c b/gcc/optabs.c
index 983c8d9..8926efa 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -6784,14 +6784,18 @@ expand_vec_perm (machine_mode mode, rtx v0, rtx v1, rtx sel, rtx target)
     {
       /* Multiply each element by its byte size.  */
       machine_mode selmode = GET_MODE (sel);
+      /* We cannot re-use SEL as a temp operand since it might by in
+	 read-only storage.  */
+      rtx sel_reg = gen_reg_rtx (selmode);
+
       if (u == 2)
-	sel = expand_simple_binop (selmode, PLUS, sel, sel,
-				   sel, 0, OPTAB_DIRECT);
+	sel_reg = expand_simple_binop (selmode, PLUS, sel, sel,
+				       sel_reg, 0, OPTAB_DIRECT);
       else
-	sel = expand_simple_binop (selmode, ASHIFT, sel,
-				   GEN_INT (exact_log2 (u)),
-				   sel, 0, OPTAB_DIRECT);
-      gcc_assert (sel != NULL);
+	sel_reg = expand_simple_binop (selmode, ASHIFT, sel,
+				       GEN_INT (exact_log2 (u)),
+				       sel_reg, 0, OPTAB_DIRECT);
+      gcc_assert (sel_reg != NULL);
 
       /* Broadcast the low byte each element into each of its bytes.  */
       vec = rtvec_alloc (w);
@@ -6803,7 +6807,7 @@ expand_vec_perm (machine_mode mode, rtx v0, rtx v1, rtx sel, rtx target)
 	  RTVEC_ELT (vec, i) = GEN_INT (this_e);
 	}
       tmp = gen_rtx_CONST_VECTOR (qimode, vec);
-      sel = gen_lowpart (qimode, sel);
+      sel = gen_lowpart (qimode, sel_reg);
       sel = expand_vec_perm (qimode, sel, sel, tmp, NULL);
       gcc_assert (sel != NULL);
 
-- 
1.7.9.5