intel/brw: Split out 64-bit lowering from algebraic optimizations

We don't necessarily want to split up MOVs for 64-bit addresses into
2x 32-bit MOVs right away, as this makes things like copy propagating
the whole address around harder.  We should do this late, once, while
still doing other algebraic optimizations earlier.

fossil-db results for Alchemist show tiny improvements:

   Totals:
   Instrs: 161310502 -> 161310436 (-0.00%); split: -0.00%, +0.00%
   Cycles: 14370605606 -> 14370605159 (-0.00%); split: -0.00%, +0.00%

   Totals from 33 (0.01% of 652298) affected shaders:
   Instrs: 15053 -> 14987 (-0.44%); split: -0.64%, +0.20%
   Cycles: 196947 -> 196500 (-0.23%); split: -0.25%, +0.02%

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28286>

4 files changed, 101 insertions, 72 deletions

diff --git a/src/intel/compiler/brw_fs.h b/src/intel/compiler/brw_fs.h
index 895a449b1ac..a36ec900b71 100644
--- a/src/intel/compiler/brw_fs.h
+++ b/src/intel/compiler/brw_fs.h
@@ -593,6 +593,7 @@ void nir_to_brw(fs_visitor *s);
 void brw_fs_optimize(fs_visitor &s);
 
 bool brw_fs_lower_3src_null_dest(fs_visitor &s);
+bool brw_fs_lower_alu_restrictions(fs_visitor &s);
 bool brw_fs_lower_barycentrics(fs_visitor &s);
 bool brw_fs_lower_constant_loads(fs_visitor &s);
 bool brw_fs_lower_derivatives(fs_visitor &s);
diff --git a/src/intel/compiler/brw_fs_lower.cpp b/src/intel/compiler/brw_fs_lower.cpp
index ff038b3961a..c8ce381aa31 100644
--- a/src/intel/compiler/brw_fs_lower.cpp
+++ b/src/intel/compiler/brw_fs_lower.cpp
@@ -562,3 +562,101 @@ brw_fs_lower_3src_null_dest(fs_visitor &s)
    return progress;
 }
 
+/**
+ * Perform lowering to legalize the IR for various ALU restrictions.
+ *
+ * For example:
+ * - Splitting 64-bit MOV/SEL into 2x32-bit where needed
+ */
+bool
+brw_fs_lower_alu_restrictions(fs_visitor &s)
+{
+   const intel_device_info *devinfo = s.devinfo;
+   bool progress = false;
+
+   foreach_block_and_inst_safe(block, fs_inst, inst, s.cfg) {
+      switch (inst->opcode) {
+      case BRW_OPCODE_MOV:
+         if (!devinfo->has_64bit_float &&
+             inst->dst.type == BRW_REGISTER_TYPE_DF) {
+            assert(inst->dst.type == inst->src[0].type);
+            assert(!inst->saturate);
+            assert(!inst->src[0].abs);
+            assert(!inst->src[0].negate);
+            const brw::fs_builder ibld(&s, block, inst);
+
+            if (!inst->is_partial_write())
+               ibld.emit_undef_for_dst(inst);
+
+            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_F, 1),
+                     subscript(inst->src[0], BRW_REGISTER_TYPE_F, 1));
+            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_F, 0),
+                     subscript(inst->src[0], BRW_REGISTER_TYPE_F, 0));
+
+            inst->remove(block);
+            progress = true;
+         }
+
+         if (!devinfo->has_64bit_int &&
+             (inst->dst.type == BRW_REGISTER_TYPE_UQ ||
+              inst->dst.type == BRW_REGISTER_TYPE_Q)) {
+            assert(inst->dst.type == inst->src[0].type);
+            assert(!inst->saturate);
+            assert(!inst->src[0].abs);
+            assert(!inst->src[0].negate);
+            const brw::fs_builder ibld(&s, block, inst);
+
+            if (!inst->is_partial_write())
+               ibld.emit_undef_for_dst(inst);
+
+            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 1),
+                     subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 1));
+            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 0),
+                     subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 0));
+
+            inst->remove(block);
+            progress = true;
+         }
+         break;
+
+      case BRW_OPCODE_SEL:
+         if (!devinfo->has_64bit_float &&
+             !devinfo->has_64bit_int &&
+             (inst->dst.type == BRW_REGISTER_TYPE_DF ||
+              inst->dst.type == BRW_REGISTER_TYPE_UQ ||
+              inst->dst.type == BRW_REGISTER_TYPE_Q)) {
+            assert(inst->dst.type == inst->src[0].type);
+            assert(!inst->saturate);
+            assert(!inst->src[0].abs && !inst->src[0].negate);
+            assert(!inst->src[1].abs && !inst->src[1].negate);
+            const brw::fs_builder ibld(&s, block, inst);
+
+            if (!inst->is_partial_write())
+               ibld.emit_undef_for_dst(inst);
+
+            set_predicate(inst->predicate,
+                          ibld.SEL(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 0),
+                                   subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 0),
+                                   subscript(inst->src[1], BRW_REGISTER_TYPE_UD, 0)));
+            set_predicate(inst->predicate,
+                          ibld.SEL(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 1),
+                                   subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 1),
+                                   subscript(inst->src[1], BRW_REGISTER_TYPE_UD, 1)));
+
+            inst->remove(block);
+            progress = true;
+         }
+         break;
+
+      default:
+         break;
+      }
+   }
+
+   if (progress) {
+      s.invalidate_analysis(DEPENDENCY_INSTRUCTION_DATA_FLOW |
+                            DEPENDENCY_INSTRUCTION_DETAIL);
+   }
+
+   return progress;
+}
diff --git a/src/intel/compiler/brw_fs_opt.cpp b/src/intel/compiler/brw_fs_opt.cpp
index f7a1f2a618a..7835d060084 100644
--- a/src/intel/compiler/brw_fs_opt.cpp
+++ b/src/intel/compiler/brw_fs_opt.cpp
@@ -12,7 +12,6 @@ using namespace brw;
 void
 brw_fs_optimize(fs_visitor &s)
 {
-   const intel_device_info *devinfo = s.devinfo;
    const nir_shader *nir = s.nir;
 
    s.debug_optimizer(nir, "start", 0, 0);
@@ -123,15 +122,13 @@ brw_fs_optimize(fs_visitor &s)
    if (OPT(brw_fs_lower_load_payload)) {
       OPT(brw_fs_opt_split_virtual_grfs);
 
-      /* Lower 64 bit MOVs generated by payload lowering. */
-      if (!devinfo->has_64bit_float || !devinfo->has_64bit_int)
-         OPT(brw_fs_opt_algebraic);
-
       OPT(brw_fs_opt_register_coalesce);
       OPT(brw_fs_lower_simd_width);
       OPT(brw_fs_opt_dead_code_eliminate);
    }
 
+   OPT(brw_fs_lower_alu_restrictions);
+
    OPT(brw_fs_opt_combine_constants);
    if (OPT(brw_fs_lower_integer_multiplication)) {
       /* If lower_integer_multiplication made progress, it may have produced
diff --git a/src/intel/compiler/brw_fs_opt_algebraic.cpp b/src/intel/compiler/brw_fs_opt_algebraic.cpp
index aab17ae4bdd..e92bf4c5727 100644
--- a/src/intel/compiler/brw_fs_opt_algebraic.cpp
+++ b/src/intel/compiler/brw_fs_opt_algebraic.cpp
@@ -73,47 +73,6 @@ brw_fs_opt_algebraic(fs_visitor &s)
    foreach_block_and_inst_safe(block, fs_inst, inst, s.cfg) {
       switch (inst->opcode) {
       case BRW_OPCODE_MOV:
-         if (!devinfo->has_64bit_float &&
-             inst->dst.type == BRW_REGISTER_TYPE_DF) {
-            assert(inst->dst.type == inst->src[0].type);
-            assert(!inst->saturate);
-            assert(!inst->src[0].abs);
-            assert(!inst->src[0].negate);
-            const brw::fs_builder ibld(&s, block, inst);
-
-            if (!inst->is_partial_write())
-               ibld.emit_undef_for_dst(inst);
-
-            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_F, 1),
-                     subscript(inst->src[0], BRW_REGISTER_TYPE_F, 1));
-            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_F, 0),
-                     subscript(inst->src[0], BRW_REGISTER_TYPE_F, 0));
-
-            inst->remove(block);
-            progress = true;
-         }
-
-         if (!devinfo->has_64bit_int &&
-             (inst->dst.type == BRW_REGISTER_TYPE_UQ ||
-              inst->dst.type == BRW_REGISTER_TYPE_Q)) {
-            assert(inst->dst.type == inst->src[0].type);
-            assert(!inst->saturate);
-            assert(!inst->src[0].abs);
-            assert(!inst->src[0].negate);
-            const brw::fs_builder ibld(&s, block, inst);
-
-            if (!inst->is_partial_write())
-               ibld.emit_undef_for_dst(inst);
-
-            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 1),
-                     subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 1));
-            ibld.MOV(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 0),
-                     subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 0));
-
-            inst->remove(block);
-            progress = true;
-         }
-
          if ((inst->conditional_mod == BRW_CONDITIONAL_Z ||
               inst->conditional_mod == BRW_CONDITIONAL_NZ) &&
              inst->dst.is_null() &&
@@ -299,32 +258,6 @@ brw_fs_opt_algebraic(fs_visitor &s)
          }
          break;
       case BRW_OPCODE_SEL:
-         if (!devinfo->has_64bit_float &&
-             !devinfo->has_64bit_int &&
-             (inst->dst.type == BRW_REGISTER_TYPE_DF ||
-              inst->dst.type == BRW_REGISTER_TYPE_UQ ||
-              inst->dst.type == BRW_REGISTER_TYPE_Q)) {
-            assert(inst->dst.type == inst->src[0].type);
-            assert(!inst->saturate);
-            assert(!inst->src[0].abs && !inst->src[0].negate);
-            assert(!inst->src[1].abs && !inst->src[1].negate);
-            const brw::fs_builder ibld(&s, block, inst);
-
-            if (!inst->is_partial_write())
-               ibld.emit_undef_for_dst(inst);
-
-            set_predicate(inst->predicate,
-                          ibld.SEL(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 0),
-                                   subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 0),
-                                   subscript(inst->src[1], BRW_REGISTER_TYPE_UD, 0)));
-            set_predicate(inst->predicate,
-                          ibld.SEL(subscript(inst->dst, BRW_REGISTER_TYPE_UD, 1),
-                                   subscript(inst->src[0], BRW_REGISTER_TYPE_UD, 1),
-                                   subscript(inst->src[1], BRW_REGISTER_TYPE_UD, 1)));
-
-            inst->remove(block);
-            progress = true;
-         }
          if (inst->src[0].equals(inst->src[1])) {
             inst->opcode = BRW_OPCODE_MOV;
             inst->sources = 1;