Re: [PATCH v3 6/8] gcn: Add else operand to masked loads.

[Andrew Stubbs]

On 02/11/2024 12:58, Robin Dapp wrote:

From: Robin Dapp <rd...@ventanamicro.com>

This patch adds an undefined else operand to the masked loads.

gcc/ChangeLog:

        * config/gcn/predicates.md (maskload_else_operand): New
        predicate.
        * config/gcn/gcn-valu.md: Use new predicate.
---
  gcc/config/gcn/gcn-valu.md   | 14 +++++---------
  gcc/config/gcn/predicates.md |  2 ++
  2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/gcc/config/gcn/gcn-valu.md b/gcc/config/gcn/gcn-valu.md
index cb2f4a78035..0e65521cf37 100644
--- a/gcc/config/gcn/gcn-valu.md
+++ b/gcc/config/gcn/gcn-valu.md
@@ -3989,7 +3989,8 @@ (define_expand "while_ultsidi"
  (define_expand "maskload<mode>di"
    [(match_operand:V_MOV 0 "register_operand")
     (match_operand:V_MOV 1 "memory_operand")
-   (match_operand 2 "")]
+   (match_operand 2 "")
+   (match_operand:V_MOV 3 "maskload_else_operand")]
    ""
    {
      rtx exec = force_reg (DImode, operands[2]);
@@ -3998,11 +3999,8 @@ (define_expand "maskload<mode>di"
      rtx as = gen_rtx_CONST_INT (VOIDmode, MEM_ADDR_SPACE (operands[1]));
      rtx v = gen_rtx_CONST_INT (VOIDmode, MEM_VOLATILE_P (operands[1]));

- /* Masked lanes are required to hold zero. */

-    emit_move_insn (operands[0], gcn_vec_constant (<MODE>mode, 0));
-
      emit_insn (gen_gather<mode>_expr_exec (operands[0], addr, as, v,
-                                          operands[0], exec));
+                                          gcn_gen_undef(<MODE>mode), exec));
      DONE;
    })

@@ -4027,7 +4025,8 @@ (define_expand "mask_gather_load<mode><vnsi>"

     (match_operand:<VnSI> 2 "register_operand")
     (match_operand 3 "immediate_operand")
     (match_operand:SI 4 "gcn_alu_operand")
-   (match_operand:DI 5 "")]
+   (match_operand:DI 5 "")
+   (match_operand:V_MOV 6 "maskload_else_operand")]
    ""
    {
      rtx exec = force_reg (DImode, operands[5]);
@@ -4036,9 +4035,6 @@ (define_expand "mask_gather_load<mode><vnsi>"
                                          operands[2], operands[4],
                                          INTVAL (operands[3]), exec);

- /* Masked lanes are required to hold zero. */

-    emit_move_insn (operands[0], gcn_vec_constant (<MODE>mode, 0));
-
      if (GET_MODE (addr) == <VnDI>mode)
        emit_insn (gen_gather<mode>_insn_1offset_exec (operands[0], addr,
                                                     const0_rtx, const0_rtx,

This needs the same gcn_gen_undef as the other instance.

diff --git a/gcc/config/gcn/predicates.md b/gcc/config/gcn/predicates.md
index 3f59396a649..21beeb586a4 100644
--- a/gcc/config/gcn/predicates.md
+++ b/gcc/config/gcn/predicates.md
@@ -228,3 +228,5 @@ (define_predicate "ascending_zero_int_parallel"
    return gcn_stepped_zero_int_parallel_p (op, 1);
  })

+(define_predicate "maskload_else_operand"

+  (match_operand 0 "scratch_operand"))

Otherwise, this patch is OK.

Andrew