[PATCH 13/14][AArch64_be] Fix vec_shr pattern to correctly implement endianness-neutral optab

[Alan Lawrence]

The previous patch broke aarch64_be by redefining VEC_RSHIFT_EXPR / 
vec_shr_optab to always shift the vector towards gcc's element 0. This fixes 
aarch64_be to do that.

check-gcc on aarch64-none-elf (no changes) and aarch64_be-none-elf (fixes all 
regressions produced by previous patch, i.e. no regressions from before 
redefining vec_shr).


gcc/ChangeLog:

        * config/aarch64/aarch64-simd.md (vec_shr_<mode> *2): Fix bigendian.


diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md
index 3fcf809113d73b37a95653b8c2be432478d2bc1e..e45eddbda7528cfbb4b0953b2c9934c5408d2f6d 100644
--- a/gcc/config/aarch64/aarch64-simd.md
+++ b/gcc/config/aarch64/aarch64-simd.md
@@ -776,7 +776,12 @@
         (lshiftrt:VD (match_operand:VD 1 "register_operand" "w")
 		     (match_operand:SI 2 "immediate_operand" "i")))]
   "TARGET_SIMD"
-  "ushr %d0, %d1, %2"
+  {
+    if (BYTES_BIG_ENDIAN)
+      return "ushl %d0, %d1, %2";
+    else
+      return "ushr %d0, %d1, %2";
+  }
   [(set_attr "type" "neon_shift_imm")]
 )
 
@@ -804,6 +809,14 @@
       DONE;
     }
 
+  if (BYTES_BIG_ENDIAN)
+    {
+      rtx temp = operands[1];
+      operands[1] = zero_reg;
+      zero_reg = temp;
+      num_bits = 128 - num_bits;
+    }
+
   emit_insn (gen_aarch64_ext<mode> (operands[0], operands[1], zero_reg,
 		      GEN_INT (num_bits / elem_bits)));
   DONE;