[gcc r12-914] aarch64: Relax aarch64_<sur><addsub>hn2<mode> RTL pattern

[gcc r12-914] aarch64: Relax aarch64_<sur><addsub>hn2<mode> RTL pattern

[Jonathan Wright]

https://gcc.gnu.org/g:3eddaad02dcce21fb67c42cc6e1e8f951a630ac1

commit r12-914-g3eddaad02dcce21fb67c42cc6e1e8f951a630ac1
Author: Jonathan Wright <jonathan.wright@arm.com>
Date:   Wed Mar 3 16:59:28 2021 +0000

    aarch64: Relax aarch64_<sur><addsub>hn2<mode> RTL pattern
    
    Implement v[r]addhn2 and v[r]subhn2 Neon intrinsic RTL patterns using
    a vec_concat of a register_operand and an ADDSUBHN unspec - instead
    of just an ADDSUBHN2 unspec. This more relaxed pattern allows for
    more aggressive combinations and ultimately better code generation.
    
    This patch also removes the now redundant [R]ADDHN2 and [R]SUBHN2
    unspecs and their iterator.
    
    gcc/ChangeLog:
    
    2021-03-03  Jonathan Wright  <jonathan.wright@arm.com>
    
            * config/aarch64/aarch64-simd.md (aarch64_<sur><addsub>hn2<mode>):
            Implement as an expand emitting a big/little endian
            instruction pattern.
            (aarch64_<sur><addsub>hn2<mode>_insn_le): Define.
            (aarch64_<sur><addsub>hn2<mode>_insn_be): Define.
            * config/aarch64/iterators.md: Remove UNSPEC_[R]ADDHN2 and
            UNSPEC_[R]SUBHN2 unspecs and ADDSUBHN2 iterator.

Diff:
---
 gcc/config/aarch64/aarch64-simd.md | 43 ++++++++++++++++++++++++++++++++------
 gcc/config/aarch64/iterators.md    | 15 +------------
 2 files changed, 38 insertions(+), 20 deletions(-)

diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md
index e59bc7b4583..1efc854a2ec 100644
--- a/gcc/config/aarch64/aarch64-simd.md
+++ b/gcc/config/aarch64/aarch64-simd.md
@@ -4594,17 +4594,48 @@
   [(set_attr "type" "neon_<addsub>_halve_narrow_q")]
 )
 
-(define_insn "aarch64_<sur><addsub>hn2<mode>"
+(define_insn "aarch64_<sur><addsub>hn2<mode>_insn_le"
   [(set (match_operand:<VNARROWQ2> 0 "register_operand" "=w")
-        (unspec:<VNARROWQ2> [(match_operand:<VNARROWQ> 1 "register_operand" "0")
-			     (match_operand:VQN 2 "register_operand" "w")
-			     (match_operand:VQN 3 "register_operand" "w")]
-                            ADDSUBHN2))]
-  "TARGET_SIMD"
+	(vec_concat:<VNARROWQ2>
+	  (match_operand:<VNARROWQ> 1 "register_operand" "0")
+	  (unspec:<VNARROWQ> [(match_operand:VQN 2 "register_operand" "w")
+			      (match_operand:VQN 3 "register_operand" "w")]
+			     ADDSUBHN)))]
+  "TARGET_SIMD && !BYTES_BIG_ENDIAN"
+  "<sur><addsub>hn2\\t%0.<V2ntype>, %2.<Vtype>, %3.<Vtype>"
+  [(set_attr "type" "neon_<addsub>_halve_narrow_q")]
+)
+
+(define_insn "aarch64_<sur><addsub>hn2<mode>_insn_be"
+  [(set (match_operand:<VNARROWQ2> 0 "register_operand" "=w")
+	(vec_concat:<VNARROWQ2>
+	  (unspec:<VNARROWQ> [(match_operand:VQN 2 "register_operand" "w")
+			      (match_operand:VQN 3 "register_operand" "w")]
+			     ADDSUBHN)
+	  (match_operand:<VNARROWQ> 1 "register_operand" "0")))]
+  "TARGET_SIMD && BYTES_BIG_ENDIAN"
   "<sur><addsub>hn2\\t%0.<V2ntype>, %2.<Vtype>, %3.<Vtype>"
   [(set_attr "type" "neon_<addsub>_halve_narrow_q")]
 )
 
+(define_expand "aarch64_<sur><addsub>hn2<mode>"
+  [(match_operand:<VNARROWQ2> 0 "register_operand")
+   (match_operand:<VNARROWQ> 1 "register_operand")
+   (unspec [(match_operand:VQN 2 "register_operand")
+	    (match_operand:VQN 3 "register_operand")]
+	   ADDSUBHN)]
+  "TARGET_SIMD"
+  {
+    if (BYTES_BIG_ENDIAN)
+      emit_insn (gen_aarch64_<sur><addsub>hn2<mode>_insn_be (operands[0],
+				operands[1], operands[2], operands[3]));
+    else
+      emit_insn (gen_aarch64_<sur><addsub>hn2<mode>_insn_le (operands[0],
+				operands[1], operands[2], operands[3]));
+    DONE;
+  }
+)
+
 ;; pmul.
 
 (define_insn "aarch64_pmul<mode>"
diff --git a/gcc/config/aarch64/iterators.md b/gcc/config/aarch64/iterators.md
index f133bfdebbd..29ce6690e9d 100644
--- a/gcc/config/aarch64/iterators.md
+++ b/gcc/config/aarch64/iterators.md
@@ -514,10 +514,6 @@
     UNSPEC_RADDHN	; Used in aarch64-simd.md.
     UNSPEC_SUBHN	; Used in aarch64-simd.md.
     UNSPEC_RSUBHN	; Used in aarch64-simd.md.
-    UNSPEC_ADDHN2	; Used in aarch64-simd.md.
-    UNSPEC_RADDHN2	; Used in aarch64-simd.md.
-    UNSPEC_SUBHN2	; Used in aarch64-simd.md.
-    UNSPEC_RSUBHN2	; Used in aarch64-simd.md.
     UNSPEC_SQDMULH	; Used in aarch64-simd.md.
     UNSPEC_SQRDMULH	; Used in aarch64-simd.md.
     UNSPEC_PMUL		; Used in aarch64-simd.md.
@@ -2241,9 +2237,6 @@
 (define_int_iterator ADDSUBHN [UNSPEC_ADDHN UNSPEC_RADDHN
 			       UNSPEC_SUBHN UNSPEC_RSUBHN])
 
-(define_int_iterator ADDSUBHN2 [UNSPEC_ADDHN2 UNSPEC_RADDHN2
-			        UNSPEC_SUBHN2 UNSPEC_RSUBHN2])
-
 (define_int_iterator FMAXMIN_UNS [UNSPEC_FMAX UNSPEC_FMIN
 				  UNSPEC_FMAXNM UNSPEC_FMINNM])
 
@@ -3000,8 +2993,6 @@
 		      (UNSPEC_SABDL2 "s") (UNSPEC_UABDL2 "u")
 		      (UNSPEC_SADALP "s") (UNSPEC_UADALP "u")
 		      (UNSPEC_SUBHN "") (UNSPEC_RSUBHN "r")
-		      (UNSPEC_ADDHN2 "") (UNSPEC_RADDHN2 "r")
-		      (UNSPEC_SUBHN2 "") (UNSPEC_RSUBHN2 "r")
 		      (UNSPEC_USQADD "us") (UNSPEC_SUQADD "su")
 		      (UNSPEC_SSLI  "s") (UNSPEC_USLI  "u")
 		      (UNSPEC_SSRI  "s") (UNSPEC_USRI  "u")
@@ -3064,11 +3055,7 @@
 			 (UNSPEC_ADDHN "add")
 			 (UNSPEC_SUBHN "sub")
 			 (UNSPEC_RADDHN "add")
-			 (UNSPEC_RSUBHN "sub")
-			 (UNSPEC_ADDHN2 "add")
-			 (UNSPEC_SUBHN2 "sub")
-			 (UNSPEC_RADDHN2 "add")
-			 (UNSPEC_RSUBHN2 "sub")])
+			 (UNSPEC_RSUBHN "sub")])
 
 ;; BSL variants: first commutative operand.
 (define_int_attr bsl_1st [(1 "w") (2 "0")])