[PATCH][AArch64] Use @ pattern to eliminate switch statement in one more place

[Kyrylo Tkachov]

Hi all,

We can use the new '@' modifier to MD patterns to generate mode-parametrised 
gen_ functions
for the despeculate_copy patterns and therefore remove the switch on modes in 
aarch64.c
that is used to pick the right generator. This simplifies the code.

Bootstrapped and tested on aarch64-none-linux-gnu.

Ok for trunk?

Thanks,
Kyrill

2018-10-16  Kyrylo Tkachov  <kyrylo.tkac...@arm.com>

    * config/aarch64/aarch64.md (despeculate_copy<ALLI_TI:mode>):
    Rename to...
    (@despeculate_copy<ALLI_TI:mode>): ... This.
    * config/aarch64/aarch64.c (aarch64_speculation_safe_value): Remove
    switch statement.

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 34d08a075221fd4c098e9b5e8fabd8fe3948d285..03041c5af99e52de8f5b4d8342e93ef2b90985bc 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -17968,26 +17968,7 @@ aarch64_speculation_safe_value (machine_mode mode,
   if (!aarch64_reg_or_zero (failval, mode))
     failval = copy_to_mode_reg (mode, failval);
 
-  switch (mode)
-    {
-    case E_QImode:
-      emit_insn (gen_despeculate_copyqi (result, val, failval));
-      break;
-    case E_HImode:
-      emit_insn (gen_despeculate_copyhi (result, val, failval));
-      break;
-    case E_SImode:
-      emit_insn (gen_despeculate_copysi (result, val, failval));
-      break;
-    case E_DImode:
-      emit_insn (gen_despeculate_copydi (result, val, failval));
-      break;
-    case E_TImode:
-      emit_insn (gen_despeculate_copyti (result, val, failval));
-      break;
-    default:
-      gcc_unreachable ();
-    }
+  emit_insn (gen_despeculate_copy (mode, result, val, failval));
   return result;
 }
 
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 4170d3fbb00c733a1411e726a67af17052800307..32d6f138232c617213f0d3488db49cb3546eb0a9 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -6743,7 +6743,7 @@ (define_insn "speculation_barrier"
 ;; Support for __builtin_speculation_safe_value when we have speculation
 ;; tracking enabled.  Use the speculation tracker to decide whether to
 ;; copy operand 1 to the target, or to copy the fail value (operand 2).
-(define_expand "despeculate_copy<ALLI_TI:mode>"
+(define_expand "@despeculate_copy<ALLI_TI:mode>"
   [(set (match_operand:ALLI_TI 0 "register_operand" "=r")
 	(unspec_volatile:ALLI_TI
 	 [(match_operand:ALLI_TI 1 "register_operand" "r")