[PATCH] aarch64: Use RTL builtins for [su]mull_n intrinsics

[Jonathan Wright via Gcc-patches]

Hi,

As subject, this patch rewrites [su]mull_n Neon intrinsics to use RTL builtins
rather than inline assembly code, allowing for better scheduling and
optimization.

Regression tested and bootstrapped on aarch64-none-linux-gnu - no
issues.

Ok for master?

Thanks,
Jonathan

gcc/ChangeLog:

2021-01-19  Jonathan Wright  <jonathan.wri...@arm.com>

        * config/aarch64/aarch64-simd-builtins.def: Add [su]mull_n
        builtin generator macros.
        * config/aarch64/aarch64-simd.md (aarch64_<su>mull_n<mode>):
        Define.
        * config/aarch64/arm_neon.h (vmull_n_s16): Use RTL builtin
        instead of inline asm.
        (vmull_n_s32): Likewise.
        (vmull_n_u16): Likewise.
        (vmull_n_u32): Likewise.

diff --git a/gcc/config/aarch64/aarch64-simd-builtins.def b/gcc/config/aarch64/aarch64-simd-builtins.def
index 4913231ea55260fea1c7511a28a436e1e1e2ab20..198aa7e85423c8f5fd7abbdbaae6ce1fc6d9c37f 100644
--- a/gcc/config/aarch64/aarch64-simd-builtins.def
+++ b/gcc/config/aarch64/aarch64-simd-builtins.def
@@ -255,6 +255,9 @@
   BUILTIN_VQW (BINOP, vec_widen_smult_hi_, 10, NONE)
   BUILTIN_VQW (BINOPU, vec_widen_umult_hi_, 10, NONE)
 
+  BUILTIN_VD_HSI (BINOP, smull_n, 0, NONE)
+  BUILTIN_VD_HSI (BINOPU, umull_n, 0, NONE)
+
   BUILTIN_VD_HSI (TERNOP_LANE, vec_smult_lane_, 0, ALL)
   BUILTIN_VD_HSI (QUADOP_LANE, vec_smlal_lane_, 0, ALL)
   BUILTIN_VD_HSI (TERNOP_LANE, vec_smult_laneq_, 0, ALL)
diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md
index adeec028d49f06156a5e84ce4dd83dbd6f151474..912b94bcfd731fdab9a813bf1a089d025fbd4a89 100644
--- a/gcc/config/aarch64/aarch64-simd.md
+++ b/gcc/config/aarch64/aarch64-simd.md
@@ -2061,6 +2061,19 @@
   [(set_attr "type" "neon_mul_<Vetype>_scalar_long")]
 )
 
+(define_insn "aarch64_<su>mull_n<mode>"
+  [(set (match_operand:<VWIDE> 0 "register_operand" "=w")
+        (mult:<VWIDE>
+          (ANY_EXTEND:<VWIDE>
+            (vec_duplicate:<VCOND>
+	      (match_operand:<VEL> 2 "register_operand" "<h_con>")))
+          (ANY_EXTEND:<VWIDE>
+            (match_operand:VD_HSI 1 "register_operand" "w"))))]
+  "TARGET_SIMD"
+  "<su>mull\t%0.<Vwtype>, %1.<Vtype>, %2.<Vetype>[0]"
+  [(set_attr "type" "neon_mul_<Vetype>_scalar_long")]
+)
+
 ;; vmlal_lane_s16 intrinsics
 (define_insn "aarch64_vec_<su>mlal_lane<Qlane>"
   [(set (match_operand:<VWIDE> 0 "register_operand" "=w")
diff --git a/gcc/config/aarch64/arm_neon.h b/gcc/config/aarch64/arm_neon.h
index 2a71ca9aa3c8c4095e99aa08c48e583f037a41ed..57959b6b0e22d44048e735e92ed7f578ec4153ea 100644
--- a/gcc/config/aarch64/arm_neon.h
+++ b/gcc/config/aarch64/arm_neon.h
@@ -8799,48 +8799,28 @@ __extension__ extern __inline int32x4_t
 __attribute__ ((__always_inline__, __gnu_inline__, __artificial__))
 vmull_n_s16 (int16x4_t __a, int16_t __b)
 {
-  int32x4_t __result;
-  __asm__ ("smull %0.4s,%1.4h,%2.h[0]"
-           : "=w"(__result)
-           : "w"(__a), "x"(__b)
-           : /* No clobbers */);
-  return __result;
+  return __builtin_aarch64_smull_nv4hi (__a, __b);
 }
 
 __extension__ extern __inline int64x2_t
 __attribute__ ((__always_inline__, __gnu_inline__, __artificial__))
 vmull_n_s32 (int32x2_t __a, int32_t __b)
 {
-  int64x2_t __result;
-  __asm__ ("smull %0.2d,%1.2s,%2.s[0]"
-           : "=w"(__result)
-           : "w"(__a), "w"(__b)
-           : /* No clobbers */);
-  return __result;
+  return __builtin_aarch64_smull_nv2si (__a, __b);
 }
 
 __extension__ extern __inline uint32x4_t
 __attribute__ ((__always_inline__, __gnu_inline__, __artificial__))
 vmull_n_u16 (uint16x4_t __a, uint16_t __b)
 {
-  uint32x4_t __result;
-  __asm__ ("umull %0.4s,%1.4h,%2.h[0]"
-           : "=w"(__result)
-           : "w"(__a), "x"(__b)
-           : /* No clobbers */);
-  return __result;
+  return __builtin_aarch64_umull_nv4hi_uuu (__a, __b);
 }
 
 __extension__ extern __inline uint64x2_t
 __attribute__ ((__always_inline__, __gnu_inline__, __artificial__))
 vmull_n_u32 (uint32x2_t __a, uint32_t __b)
 {
-  uint64x2_t __result;
-  __asm__ ("umull %0.2d,%1.2s,%2.s[0]"
-           : "=w"(__result)
-           : "w"(__a), "w"(__b)
-           : /* No clobbers */);
-  return __result;
+  return __builtin_aarch64_umull_nv2si_uuu (__a, __b);
 }
 
 __extension__ extern __inline poly16x8_t