[v3,5/8] aarch64: Add masked-load else operands.

Message ID 20241102125828.29183-6-rdapp.gcc@gmail.com
State New
Headers
Series Rebased: Add maskload else operand. |

Checks

Context Check Description
linaro-tcwg-bot/tcwg_gcc_build--master-arm success Build passed
linaro-tcwg-bot/tcwg_gcc_build--master-aarch64 success Build passed
linaro-tcwg-bot/tcwg_gcc_check--master-aarch64 success Test passed
linaro-tcwg-bot/tcwg_gcc_check--master-arm success Test passed

Commit Message

Robin Dapp Nov. 2, 2024, 12:58 p.m. UTC
  From: Robin Dapp <rdapp@ventanamicro.com>

This adds zero else operands to masked loads and their intrinsics.
I needed to adjust more than initially thought because we rely on
combine for several instructions and a change in a "base" pattern
needs to propagate to all those.

gcc/ChangeLog:

	* config/aarch64/aarch64-sve-builtins-base.cc: Add else
	handling.
	* config/aarch64/aarch64-sve-builtins.cc (function_expander::use_contiguous_load_insn):
	Ditto.
	* config/aarch64/aarch64-sve-builtins.h: Add else operand to
	contiguous load.
	* config/aarch64/aarch64-sve.md (@aarch64_load<SVE_PRED_LOAD:pred_load>
	_<ANY_EXTEND:optab><SVE_HSDI:mode><SVE_PARTIAL_I:mode>):
	Split and add else operand.
	(@aarch64_load_<ANY_EXTEND:optab><SVE_HSDI:mode><SVE_PARTIAL_I:mode>):
	Ditto.
	(*aarch64_load_<ANY_EXTEND:optab>_mov<SVE_HSDI:mode><SVE_PARTIAL_I:mode>):
	Ditto.
	* config/aarch64/aarch64-sve2.md: Ditto.
	* config/aarch64/iterators.md: Remove unused iterators.
	* config/aarch64/predicates.md (aarch64_maskload_else_operand):
	Add zero else operand.
---
 .../aarch64/aarch64-sve-builtins-base.cc      | 24 +++++----
 gcc/config/aarch64/aarch64-sve-builtins.cc    | 12 ++++-
 gcc/config/aarch64/aarch64-sve-builtins.h     |  2 +-
 gcc/config/aarch64/aarch64-sve.md             | 52 ++++++++++++++++---
 gcc/config/aarch64/aarch64-sve2.md            |  3 +-
 gcc/config/aarch64/iterators.md               |  4 --
 gcc/config/aarch64/predicates.md              |  4 ++
 7 files changed, 77 insertions(+), 24 deletions(-)
  

Patch

diff --git a/gcc/config/aarch64/aarch64-sve-builtins-base.cc b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
index fe16d93adcd..d840f590202 100644
--- a/gcc/config/aarch64/aarch64-sve-builtins-base.cc
+++ b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
@@ -1523,11 +1523,12 @@  public:
     gimple_seq stmts = NULL;
     tree pred = f.convert_pred (stmts, vectype, 0);
     tree base = f.fold_contiguous_base (stmts, vectype);
+    tree els = build_zero_cst (vectype);
     gsi_insert_seq_before (f.gsi, stmts, GSI_SAME_STMT);
 
     tree cookie = f.load_store_cookie (TREE_TYPE (vectype));
-    gcall *new_call = gimple_build_call_internal (IFN_MASK_LOAD, 3,
-						  base, cookie, pred);
+    gcall *new_call = gimple_build_call_internal (IFN_MASK_LOAD, 4,
+						  base, cookie, pred, els);
     gimple_call_set_lhs (new_call, f.lhs);
     return new_call;
   }
@@ -1541,7 +1542,7 @@  public:
 				     e.vector_mode (0), e.gp_mode (0));
     else
       icode = code_for_aarch64 (UNSPEC_LD1_COUNT, e.tuple_mode (0));
-    return e.use_contiguous_load_insn (icode);
+    return e.use_contiguous_load_insn (icode, true);
   }
 };
 
@@ -1554,10 +1555,10 @@  public:
   rtx
   expand (function_expander &e) const override
   {
-    insn_code icode = code_for_aarch64_load (UNSPEC_LD1_SVE, extend_rtx_code (),
+    insn_code icode = code_for_aarch64_load (extend_rtx_code (),
 					     e.vector_mode (0),
 					     e.memory_vector_mode ());
-    return e.use_contiguous_load_insn (icode);
+    return e.use_contiguous_load_insn (icode, true);
   }
 };
 
@@ -1576,6 +1577,8 @@  public:
     e.prepare_gather_address_operands (1);
     /* Put the predicate last, as required by mask_gather_load_optab.  */
     e.rotate_inputs_left (0, 5);
+    /* Add the else operand.  */
+    e.args.quick_push (CONST0_RTX (e.vector_mode (0)));
     machine_mode mem_mode = e.memory_vector_mode ();
     machine_mode int_mode = aarch64_sve_int_mode (mem_mode);
     insn_code icode = convert_optab_handler (mask_gather_load_optab,
@@ -1599,6 +1602,8 @@  public:
     e.rotate_inputs_left (0, 5);
     /* Add a constant predicate for the extension rtx.  */
     e.args.quick_push (CONSTM1_RTX (VNx16BImode));
+    /* Add the else operand.  */
+    e.args.quick_push (CONST0_RTX (e.vector_mode (1)));
     insn_code icode = code_for_aarch64_gather_load (extend_rtx_code (),
 						    e.vector_mode (0),
 						    e.memory_vector_mode ());
@@ -1741,6 +1746,7 @@  public:
     /* Get the predicate and base pointer.  */
     gimple_seq stmts = NULL;
     tree pred = f.convert_pred (stmts, vectype, 0);
+    tree els = build_zero_cst (vectype);
     tree base = f.fold_contiguous_base (stmts, vectype);
     gsi_insert_seq_before (f.gsi, stmts, GSI_SAME_STMT);
 
@@ -1759,8 +1765,8 @@  public:
 
     /* Emit the load itself.  */
     tree cookie = f.load_store_cookie (TREE_TYPE (vectype));
-    gcall *new_call = gimple_build_call_internal (IFN_MASK_LOAD_LANES, 3,
-						  base, cookie, pred);
+    gcall *new_call = gimple_build_call_internal (IFN_MASK_LOAD_LANES, 4,
+						  base, cookie, pred, els);
     gimple_call_set_lhs (new_call, lhs_array);
     gsi_insert_after (f.gsi, new_call, GSI_SAME_STMT);
 
@@ -1773,7 +1779,7 @@  public:
     machine_mode tuple_mode = e.result_mode ();
     insn_code icode = convert_optab_handler (vec_mask_load_lanes_optab,
 					     tuple_mode, e.vector_mode (0));
-    return e.use_contiguous_load_insn (icode);
+    return e.use_contiguous_load_insn (icode, true);
   }
 };
 
@@ -1844,7 +1850,7 @@  public:
 		       ? code_for_aarch64_ldnt1 (e.vector_mode (0))
 		       : code_for_aarch64 (UNSPEC_LDNT1_COUNT,
 					   e.tuple_mode (0)));
-    return e.use_contiguous_load_insn (icode);
+    return e.use_contiguous_load_insn (icode, true);
   }
 };
 
diff --git a/gcc/config/aarch64/aarch64-sve-builtins.cc b/gcc/config/aarch64/aarch64-sve-builtins.cc
index ef14f8cd39d..0db9a7e9dbe 100644
--- a/gcc/config/aarch64/aarch64-sve-builtins.cc
+++ b/gcc/config/aarch64/aarch64-sve-builtins.cc
@@ -4227,9 +4227,12 @@  function_expander::use_vcond_mask_insn (insn_code icode,
 /* Implement the call using instruction ICODE, which loads memory operand 1
    into register operand 0 under the control of predicate operand 2.
    Extending loads have a further predicate (operand 3) that nominally
-   controls the extension.  */
+   controls the extension.
+   HAS_ELSE is true if the pattern has an additional operand that specifies
+   the values of inactive lanes.  This exists to match the general maskload
+   interface and is always zero for AArch64.  */
 rtx
-function_expander::use_contiguous_load_insn (insn_code icode)
+function_expander::use_contiguous_load_insn (insn_code icode, bool has_else)
 {
   machine_mode mem_mode = memory_vector_mode ();
 
@@ -4238,6 +4241,11 @@  function_expander::use_contiguous_load_insn (insn_code icode)
   add_input_operand (icode, args[0]);
   if (GET_MODE_UNIT_BITSIZE (mem_mode) < type_suffix (0).element_bits)
     add_input_operand (icode, CONSTM1_RTX (VNx16BImode));
+
+  /* If we have an else operand, add it.  */
+  if (has_else)
+    add_input_operand (icode, CONST0_RTX (mem_mode));
+
   return generate_insn (icode);
 }
 
diff --git a/gcc/config/aarch64/aarch64-sve-builtins.h b/gcc/config/aarch64/aarch64-sve-builtins.h
index 4cdc0541bdc..1aa9caf84ba 100644
--- a/gcc/config/aarch64/aarch64-sve-builtins.h
+++ b/gcc/config/aarch64/aarch64-sve-builtins.h
@@ -695,7 +695,7 @@  public:
   rtx use_pred_x_insn (insn_code);
   rtx use_cond_insn (insn_code, unsigned int = DEFAULT_MERGE_ARGNO);
   rtx use_vcond_mask_insn (insn_code, unsigned int = DEFAULT_MERGE_ARGNO);
-  rtx use_contiguous_load_insn (insn_code);
+  rtx use_contiguous_load_insn (insn_code, bool = false);
   rtx use_contiguous_prefetch_insn (insn_code);
   rtx use_contiguous_store_insn (insn_code);
 
diff --git a/gcc/config/aarch64/aarch64-sve.md b/gcc/config/aarch64/aarch64-sve.md
index 06bd3e4bb2c..17cca97555c 100644
--- a/gcc/config/aarch64/aarch64-sve.md
+++ b/gcc/config/aarch64/aarch64-sve.md
@@ -1291,7 +1291,8 @@  (define_insn "maskload<mode><vpred>"
   [(set (match_operand:SVE_ALL 0 "register_operand" "=w")
 	(unspec:SVE_ALL
 	  [(match_operand:<VPRED> 2 "register_operand" "Upl")
-	   (match_operand:SVE_ALL 1 "memory_operand" "m")]
+	   (match_operand:SVE_ALL 1 "memory_operand" "m")
+	   (match_operand:SVE_ALL 3 "aarch64_maskload_else_operand")]
 	  UNSPEC_LD1_SVE))]
   "TARGET_SVE"
   "ld1<Vesize>\t%0.<Vctype>, %2/z, %1"
@@ -1302,11 +1303,13 @@  (define_expand "vec_load_lanes<mode><vsingle>"
   [(set (match_operand:SVE_STRUCT 0 "register_operand")
 	(unspec:SVE_STRUCT
 	  [(match_dup 2)
-	   (match_operand:SVE_STRUCT 1 "memory_operand")]
+	   (match_operand:SVE_STRUCT 1 "memory_operand")
+	   (match_dup 3)]
 	  UNSPEC_LDN))]
   "TARGET_SVE"
   {
     operands[2] = aarch64_ptrue_reg (<VPRED>mode);
+    operands[3] = CONST0_RTX (<MODE>mode);
   }
 )
 
@@ -1315,7 +1318,8 @@  (define_insn "vec_mask_load_lanes<mode><vsingle>"
   [(set (match_operand:SVE_STRUCT 0 "register_operand" "=w")
 	(unspec:SVE_STRUCT
 	  [(match_operand:<VPRED> 2 "register_operand" "Upl")
-	   (match_operand:SVE_STRUCT 1 "memory_operand" "m")]
+	   (match_operand:SVE_STRUCT 1 "memory_operand" "m")
+	   (match_operand 3 "aarch64_maskload_else_operand")]
 	  UNSPEC_LDN))]
   "TARGET_SVE"
   "ld<vector_count><Vesize>\t%0, %2/z, %1"
@@ -1334,15 +1338,16 @@  (define_insn "vec_mask_load_lanes<mode><vsingle>"
 ;; -------------------------------------------------------------------------
 
 ;; Predicated load and extend, with 8 elements per 128-bit block.
-(define_insn_and_rewrite "@aarch64_load<SVE_PRED_LOAD:pred_load>_<ANY_EXTEND:optab><SVE_HSDI:mode><SVE_PARTIAL_I:mode>"
+(define_insn_and_rewrite "@aarch64_load_<ANY_EXTEND:optab><SVE_HSDI:mode><SVE_PARTIAL_I:mode>"
   [(set (match_operand:SVE_HSDI 0 "register_operand" "=w")
 	(unspec:SVE_HSDI
 	  [(match_operand:<SVE_HSDI:VPRED> 3 "general_operand" "UplDnm")
 	   (ANY_EXTEND:SVE_HSDI
 	     (unspec:SVE_PARTIAL_I
 	       [(match_operand:<SVE_PARTIAL_I:VPRED> 2 "register_operand" "Upl")
-		(match_operand:SVE_PARTIAL_I 1 "memory_operand" "m")]
-	       SVE_PRED_LOAD))]
+		(match_operand:SVE_PARTIAL_I 1 "memory_operand" "m")
+		(match_operand:SVE_PARTIAL_I 4 "aarch64_maskload_else_operand")]
+	       UNSPEC_LD1_SVE))]
 	  UNSPEC_PRED_X))]
   "TARGET_SVE && (~<SVE_HSDI:narrower_mask> & <SVE_PARTIAL_I:self_mask>) == 0"
   "ld1<ANY_EXTEND:s><SVE_PARTIAL_I:Vesize>\t%0.<SVE_HSDI:Vctype>, %2/z, %1"
@@ -1352,6 +1357,26 @@  (define_insn_and_rewrite "@aarch64_load<SVE_PRED_LOAD:pred_load>_<ANY_EXTEND:opt
   }
 )
 
+;; Same as above without the maskload_else_operand to still allow combine to
+;; match a sign-extended pred_mov pattern.
+(define_insn_and_rewrite "*aarch64_load_<ANY_EXTEND:optab>_mov<SVE_HSDI:mode><SVE_PARTIAL_I:mode>"
+  [(set (match_operand:SVE_HSDI 0 "register_operand" "=w")
+	(unspec:SVE_HSDI
+	  [(match_operand:<SVE_HSDI:VPRED> 3 "general_operand" "UplDnm")
+	   (ANY_EXTEND:SVE_HSDI
+	     (unspec:SVE_PARTIAL_I
+	       [(match_operand:<SVE_PARTIAL_I:VPRED> 2 "register_operand" "Upl")
+		(match_operand:SVE_PARTIAL_I 1 "memory_operand" "m")]
+		UNSPEC_PRED_X))]
+	   UNSPEC_PRED_X))]
+  "TARGET_SVE && (~<SVE_HSDI:narrower_mask> & <SVE_PARTIAL_I:self_mask>) == 0"
+  "ld1<ANY_EXTEND:s><SVE_PARTIAL_I:Vesize>\t%0.<SVE_HSDI:Vctype>, %2/z, %1"
+  "&& !CONSTANT_P (operands[3])"
+  {
+    operands[3] = CONSTM1_RTX (<SVE_HSDI:VPRED>mode);
+  }
+)
+
 ;; -------------------------------------------------------------------------
 ;; ---- First-faulting contiguous loads
 ;; -------------------------------------------------------------------------
@@ -1433,7 +1458,8 @@  (define_insn "@aarch64_ldnt1<mode>"
   [(set (match_operand:SVE_FULL 0 "register_operand" "=w")
 	(unspec:SVE_FULL
 	  [(match_operand:<VPRED> 2 "register_operand" "Upl")
-	   (match_operand:SVE_FULL 1 "memory_operand" "m")]
+	   (match_operand:SVE_FULL 1 "memory_operand" "m")
+	   (match_operand:SVE_FULL 3 "aarch64_maskload_else_operand")]
 	  UNSPEC_LDNT1_SVE))]
   "TARGET_SVE"
   "ldnt1<Vesize>\t%0.<Vetype>, %2/z, %1"
@@ -1456,11 +1482,13 @@  (define_expand "gather_load<mode><v_int_container>"
 	   (match_operand:<V_INT_CONTAINER> 2 "register_operand")
 	   (match_operand:DI 3 "const_int_operand")
 	   (match_operand:DI 4 "aarch64_gather_scale_operand_<Vesize>")
+	   (match_dup 6)
 	   (mem:BLK (scratch))]
 	  UNSPEC_LD1_GATHER))]
   "TARGET_SVE && TARGET_NON_STREAMING"
   {
     operands[5] = aarch64_ptrue_reg (<VPRED>mode);
+    operands[6] = CONST0_RTX (<MODE>mode);
   }
 )
 
@@ -1474,6 +1502,7 @@  (define_insn "mask_gather_load<mode><v_int_container>"
 	   (match_operand:VNx4SI 2 "register_operand")
 	   (match_operand:DI 3 "const_int_operand")
 	   (match_operand:DI 4 "aarch64_gather_scale_operand_<Vesize>")
+	   (match_operand:SVE_4 6 "aarch64_maskload_else_operand")
 	   (mem:BLK (scratch))]
 	  UNSPEC_LD1_GATHER))]
   "TARGET_SVE && TARGET_NON_STREAMING"
@@ -1503,6 +1532,7 @@  (define_insn "mask_gather_load<mode><v_int_container>"
 	   (match_operand:VNx2DI 2 "register_operand")
 	   (match_operand:DI 3 "const_int_operand")
 	   (match_operand:DI 4 "aarch64_gather_scale_operand_<Vesize>")
+	   (match_operand:SVE_2 6 "aarch64_maskload_else_operand")
 	   (mem:BLK (scratch))]
 	  UNSPEC_LD1_GATHER))]
   "TARGET_SVE && TARGET_NON_STREAMING"
@@ -1531,6 +1561,7 @@  (define_insn_and_rewrite "*mask_gather_load<mode><v_int_container>_<su>xtw_unpac
 	     UNSPEC_PRED_X)
 	   (match_operand:DI 3 "const_int_operand")
 	   (match_operand:DI 4 "aarch64_gather_scale_operand_<Vesize>")
+	   (match_operand:SVE_2 7 "aarch64_maskload_else_operand")
 	   (mem:BLK (scratch))]
 	  UNSPEC_LD1_GATHER))]
   "TARGET_SVE && TARGET_NON_STREAMING"
@@ -1561,6 +1592,7 @@  (define_insn_and_rewrite "*mask_gather_load<mode><v_int_container>_sxtw"
 	     UNSPEC_PRED_X)
 	   (match_operand:DI 3 "const_int_operand")
 	   (match_operand:DI 4 "aarch64_gather_scale_operand_<Vesize>")
+	   (match_operand:SVE_2 7 "aarch64_maskload_else_operand")
 	   (mem:BLK (scratch))]
 	  UNSPEC_LD1_GATHER))]
   "TARGET_SVE && TARGET_NON_STREAMING"
@@ -1588,6 +1620,7 @@  (define_insn "*mask_gather_load<mode><v_int_container>_uxtw"
 	     (match_operand:VNx2DI 6 "aarch64_sve_uxtw_immediate"))
 	   (match_operand:DI 3 "const_int_operand")
 	   (match_operand:DI 4 "aarch64_gather_scale_operand_<Vesize>")
+	   (match_operand:SVE_2 7 "aarch64_maskload_else_operand")
 	   (mem:BLK (scratch))]
 	  UNSPEC_LD1_GATHER))]
   "TARGET_SVE && TARGET_NON_STREAMING"
@@ -1624,6 +1657,7 @@  (define_insn_and_rewrite "@aarch64_gather_load_<ANY_EXTEND:optab><SVE_4HSI:mode>
 		(match_operand:VNx4SI 2 "register_operand")
 		(match_operand:DI 3 "const_int_operand")
 		(match_operand:DI 4 "aarch64_gather_scale_operand_<SVE_4BHI:Vesize>")
+		(match_operand:SVE_4BHI 7 "aarch64_maskload_else_operand")
 		(mem:BLK (scratch))]
 	       UNSPEC_LD1_GATHER))]
 	  UNSPEC_PRED_X))]
@@ -1663,6 +1697,7 @@  (define_insn_and_rewrite "@aarch64_gather_load_<ANY_EXTEND:optab><SVE_2HSDI:mode
 		(match_operand:VNx2DI 2 "register_operand")
 		(match_operand:DI 3 "const_int_operand")
 		(match_operand:DI 4 "aarch64_gather_scale_operand_<SVE_2BHSI:Vesize>")
+		(match_operand:SVE_2BHSI 7 "aarch64_maskload_else_operand")
 		(mem:BLK (scratch))]
 	       UNSPEC_LD1_GATHER))]
 	  UNSPEC_PRED_X))]
@@ -1701,6 +1736,7 @@  (define_insn_and_rewrite "*aarch64_gather_load_<ANY_EXTEND:optab><SVE_2HSDI:mode
 		  UNSPEC_PRED_X)
 		(match_operand:DI 3 "const_int_operand")
 		(match_operand:DI 4 "aarch64_gather_scale_operand_<SVE_2BHSI:Vesize>")
+		(match_operand:SVE_2BHSI 8 "aarch64_maskload_else_operand")
 		(mem:BLK (scratch))]
 	       UNSPEC_LD1_GATHER))]
 	  UNSPEC_PRED_X))]
@@ -1738,6 +1774,7 @@  (define_insn_and_rewrite "*aarch64_gather_load_<ANY_EXTEND:optab><SVE_2HSDI:mode
 		  UNSPEC_PRED_X)
 		(match_operand:DI 3 "const_int_operand")
 		(match_operand:DI 4 "aarch64_gather_scale_operand_<SVE_2BHSI:Vesize>")
+		(match_operand:SVE_2BHSI 8 "aarch64_maskload_else_operand")
 		(mem:BLK (scratch))]
 	       UNSPEC_LD1_GATHER))]
 	  UNSPEC_PRED_X))]
@@ -1772,6 +1809,7 @@  (define_insn_and_rewrite "*aarch64_gather_load_<ANY_EXTEND:optab><SVE_2HSDI:mode
 		  (match_operand:VNx2DI 6 "aarch64_sve_uxtw_immediate"))
 		(match_operand:DI 3 "const_int_operand")
 		(match_operand:DI 4 "aarch64_gather_scale_operand_<SVE_2BHSI:Vesize>")
+		(match_operand:SVE_2BHSI 8 "aarch64_maskload_else_operand")
 		(mem:BLK (scratch))]
 	       UNSPEC_LD1_GATHER))]
 	  UNSPEC_PRED_X))]
diff --git a/gcc/config/aarch64/aarch64-sve2.md b/gcc/config/aarch64/aarch64-sve2.md
index 5f2697c3179..22e8632af80 100644
--- a/gcc/config/aarch64/aarch64-sve2.md
+++ b/gcc/config/aarch64/aarch64-sve2.md
@@ -138,7 +138,8 @@  (define_insn "@aarch64_<optab><mode>"
   [(set (match_operand:SVE_FULLx24 0 "aligned_register_operand" "=Uw<vector_count>")
 	(unspec:SVE_FULLx24
 	  [(match_operand:VNx16BI 2 "register_operand" "Uph")
-	   (match_operand:SVE_FULLx24 1 "memory_operand" "m")]
+	   (match_operand:SVE_FULLx24 1 "memory_operand" "m")
+	   (match_operand:SVE_FULLx24 3 "aarch64_maskload_else_operand")]
 	  LD1_COUNT))]
   "TARGET_STREAMING_SME2"
   "<optab><Vesize>\t%0, %K2/z, %1"
diff --git a/gcc/config/aarch64/iterators.md b/gcc/config/aarch64/iterators.md
index 0bc98315bb6..6592b3df3b2 100644
--- a/gcc/config/aarch64/iterators.md
+++ b/gcc/config/aarch64/iterators.md
@@ -3224,10 +3224,6 @@  (define_int_iterator SVE_SHIFT_WIDE [UNSPEC_ASHIFT_WIDE
 
 (define_int_iterator SVE_LDFF1_LDNF1 [UNSPEC_LDFF1 UNSPEC_LDNF1])
 
-(define_int_iterator SVE_PRED_LOAD [UNSPEC_PRED_X UNSPEC_LD1_SVE])
-
-(define_int_attr pred_load [(UNSPEC_PRED_X "_x") (UNSPEC_LD1_SVE "")])
-
 (define_int_iterator LD1_COUNT [UNSPEC_LD1_COUNT UNSPEC_LDNT1_COUNT])
 
 (define_int_iterator ST1_COUNT [UNSPEC_ST1_COUNT UNSPEC_STNT1_COUNT])
diff --git a/gcc/config/aarch64/predicates.md b/gcc/config/aarch64/predicates.md
index 6ad9a4bd8b9..26cfaed2402 100644
--- a/gcc/config/aarch64/predicates.md
+++ b/gcc/config/aarch64/predicates.md
@@ -1067,3 +1067,7 @@  (define_predicate "aarch64_granule16_simm9"
   (and (match_code "const_int")
        (match_test "IN_RANGE (INTVAL (op),  -4096, 4080)
 		    && !(INTVAL (op) & 0xf)")))
+
+(define_predicate "aarch64_maskload_else_operand"
+  (and (match_code "const_int,const_vector")
+       (match_test "op == CONST0_RTX (GET_MODE (op))")))