[Mesa-dev] [PATCH v3 03/48] intel/fs: Use ANY/ALL32 predicates in SIMD32

[Jason Ekstrand]

We have ANY/ALL32 predicates and, for the most part, they work just
fine.  (See the next commit for more details.)  Also, due to the way
that flag registers are handled in hardware, instruction splitting is
able to split the CMP correctly.  Specifically, that hardware looks at
the execution group and knows to shift it's flag usage up correctly so a
2H instruction will write to f0.1 instead of f0.0.

Reviewed-by: Matt Turner <mattst88 at gmail.com>
Cc: mesa-stable at lists.freedesktop.org
---
 src/intel/compiler/brw_fs_nir.cpp | 42 ++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/src/intel/compiler/brw_fs_nir.cpp b/src/intel/compiler/brw_fs_nir.cpp
index bb153ca..f29d4e8 100644
--- a/src/intel/compiler/brw_fs_nir.cpp
+++ b/src/intel/compiler/brw_fs_nir.cpp
@@ -4199,12 +4199,18 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
        * dead channels from affecting the result, we initialize the flag with
        * with the identity value for the logical operation.
        */
-      ubld.MOV(brw_flag_reg(0, 0), brw_imm_uw(0));
+      if (dispatch_width == 32) {
+         /* For SIMD32, we use a UD type so we fill both f0.0 and f0.1. */
+         ubld.MOV(retype(brw_flag_reg(0, 0), BRW_REGISTER_TYPE_UD),
+                         brw_imm_ud(0));
+      } else {
+         ubld.MOV(brw_flag_reg(0, 0), brw_imm_uw(0));
+      }
       bld.CMP(bld.null_reg_d(), get_nir_src(instr->src[0]), brw_imm_d(0), BRW_CONDITIONAL_NZ);
       bld.MOV(dest, brw_imm_d(-1));
-      set_predicate(dispatch_width == 8 ?
-                    BRW_PREDICATE_ALIGN1_ANY8H :
-                    BRW_PREDICATE_ALIGN1_ANY16H,
+      set_predicate(dispatch_width == 8  ? BRW_PREDICATE_ALIGN1_ANY8H :
+                    dispatch_width == 16 ? BRW_PREDICATE_ALIGN1_ANY16H :
+                                           BRW_PREDICATE_ALIGN1_ANY32H,
                     bld.SEL(dest, dest, brw_imm_d(0)));
       break;
    }
@@ -4215,12 +4221,18 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
        * dead channels from affecting the result, we initialize the flag with
        * with the identity value for the logical operation.
        */
-      ubld.MOV(brw_flag_reg(0, 0), brw_imm_uw(0xffff));
+      if (dispatch_width == 32) {
+         /* For SIMD32, we use a UD type so we fill both f0.0 and f0.1. */
+         ubld.MOV(retype(brw_flag_reg(0, 0), BRW_REGISTER_TYPE_UD),
+                         brw_imm_ud(0xffffffff));
+      } else {
+         ubld.MOV(brw_flag_reg(0, 0), brw_imm_uw(0xffff));
+      }
       bld.CMP(bld.null_reg_d(), get_nir_src(instr->src[0]), brw_imm_d(0), BRW_CONDITIONAL_NZ);
       bld.MOV(dest, brw_imm_d(-1));
-      set_predicate(dispatch_width == 8 ?
-                    BRW_PREDICATE_ALIGN1_ALL8H :
-                    BRW_PREDICATE_ALIGN1_ALL16H,
+      set_predicate(dispatch_width == 8  ? BRW_PREDICATE_ALIGN1_ALL8H :
+                    dispatch_width == 16 ? BRW_PREDICATE_ALIGN1_ALL16H :
+                                           BRW_PREDICATE_ALIGN1_ALL32H,
                     bld.SEL(dest, dest, brw_imm_d(0)));
       break;
    }
@@ -4233,12 +4245,18 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
        * dead channels from affecting the result, we initialize the flag with
        * with the identity value for the logical operation.
        */
-      ubld.MOV(brw_flag_reg(0, 0), brw_imm_uw(0xffff));
+      if (dispatch_width == 32) {
+         /* For SIMD32, we use a UD type so we fill both f0.0 and f0.1. */
+         ubld.MOV(retype(brw_flag_reg(0, 0), BRW_REGISTER_TYPE_UD),
+                         brw_imm_ud(0xffffffff));
+      } else {
+         ubld.MOV(brw_flag_reg(0, 0), brw_imm_uw(0xffff));
+      }
       bld.CMP(bld.null_reg_d(), value, uniformized, BRW_CONDITIONAL_Z);
       bld.MOV(dest, brw_imm_d(-1));
-      set_predicate(dispatch_width == 8 ?
-                    BRW_PREDICATE_ALIGN1_ALL8H :
-                    BRW_PREDICATE_ALIGN1_ALL16H,
+      set_predicate(dispatch_width == 8  ? BRW_PREDICATE_ALIGN1_ALL8H :
+                    dispatch_width == 16 ? BRW_PREDICATE_ALIGN1_ALL16H :
+                                           BRW_PREDICATE_ALIGN1_ALL32H,
                     bld.SEL(dest, dest, brw_imm_d(0)));
       break;
    }
-- 
2.5.0.400.gff86faf