Mesa (master): nir: Add a store_reg helper and use the builder in phis_to_regs

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Module: Mesa
Branch: master
Commit: cc4a02d0ed0755c5cf7b75757b402ea81ce54c24
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=cc4a02d0ed0755c5cf7b75757b402ea81ce54c24

Author: Jason Ekstrand <jason at jlekstrand.net>
Date:   Mon May 18 18:40:58 2020 -0500

nir: Add a store_reg helper and use the builder in phis_to_regs

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Reviewed-by: Rob Clark <robdclark at chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5094>

---

 src/compiler/nir/nir_builder.h  | 14 ++++++++++++++
 src/compiler/nir/nir_from_ssa.c | 32 +++++++++++---------------------
 2 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/src/compiler/nir/nir_builder.h b/src/compiler/nir/nir_builder.h
index 52fcf9e2250..30206962255 100644
--- a/src/compiler/nir/nir_builder.h
+++ b/src/compiler/nir/nir_builder.h
@@ -1159,6 +1159,20 @@ nir_load_reg(nir_builder *build, nir_register *reg)
    return nir_ssa_for_src(build, nir_src_for_reg(reg), reg->num_components);
 }
 
+static inline void
+nir_store_reg(nir_builder *build, nir_register *reg,
+              nir_ssa_def *def, nir_component_mask_t write_mask)
+{
+   assert(reg->num_components == def->num_components);
+   assert(reg->bit_size == def->bit_size);
+
+   nir_alu_instr *mov = nir_alu_instr_create(build->shader, nir_op_mov);
+   mov->src[0].src = nir_src_for_ssa(def);
+   mov->dest.dest = nir_dest_for_reg(reg);
+   mov->dest.write_mask = write_mask & BITFIELD_MASK(reg->num_components);
+   nir_builder_instr_insert(build, &mov->instr);
+}
+
 static inline nir_ssa_def *
 nir_load_deref_with_access(nir_builder *build, nir_deref_instr *deref,
                            enum gl_access_qualifier access)
diff --git a/src/compiler/nir/nir_from_ssa.c b/src/compiler/nir/nir_from_ssa.c
index 41ee4e79581..52c3a2cb33b 100644
--- a/src/compiler/nir/nir_from_ssa.c
+++ b/src/compiler/nir/nir_from_ssa.c
@@ -828,7 +828,7 @@ nir_convert_from_ssa(nir_shader *shader, bool phi_webs_only)
 
 
 static void
-place_phi_read(nir_shader *shader, nir_register *reg,
+place_phi_read(nir_builder *b, nir_register *reg,
                nir_ssa_def *def, nir_block *block, unsigned depth)
 {
    if (block != def->parent_instr->block) {
@@ -857,18 +857,14 @@ place_phi_read(nir_shader *shader, nir_register *reg,
           * that way.
           */
          set_foreach(block->predecessors, entry) {
-            place_phi_read(shader, reg, def, (nir_block *)entry->key,
-                           depth + 1);
+            place_phi_read(b, reg, def, (nir_block *)entry->key, depth + 1);
          }
          return;
       }
    }
 
-   nir_alu_instr *mov = nir_alu_instr_create(shader, nir_op_mov);
-   mov->src[0].src = nir_src_for_ssa(def);
-   mov->dest.dest = nir_dest_for_reg(reg);
-   mov->dest.write_mask = (1 << reg->num_components) - 1;
-   nir_instr_insert(nir_after_block_before_jump(block), &mov->instr);
+   b->cursor = nir_after_block_before_jump(block);
+   nir_store_reg(b, reg, def, ~0);
 }
 
 /** Lower all of the phi nodes in a block to imovs to and from a register
@@ -888,8 +884,8 @@ place_phi_read(nir_shader *shader, nir_register *reg,
 bool
 nir_lower_phis_to_regs_block(nir_block *block)
 {
-   nir_function_impl *impl = nir_cf_node_get_function(&block->cf_node);
-   nir_shader *shader = impl->function->shader;
+   nir_builder b;
+   nir_builder_init(&b, nir_cf_node_get_function(&block->cf_node));
 
    bool progress = false;
    nir_foreach_instr_safe(instr, block) {
@@ -899,22 +895,16 @@ nir_lower_phis_to_regs_block(nir_block *block)
       nir_phi_instr *phi = nir_instr_as_phi(instr);
       assert(phi->dest.is_ssa);
 
-      nir_register *reg = create_reg_for_ssa_def(&phi->dest.ssa, impl);
+      nir_register *reg = create_reg_for_ssa_def(&phi->dest.ssa, b.impl);
 
-      nir_alu_instr *mov = nir_alu_instr_create(shader, nir_op_mov);
-      mov->src[0].src = nir_src_for_reg(reg);
-      mov->dest.write_mask = (1 << phi->dest.ssa.num_components) - 1;
-      nir_ssa_dest_init(&mov->instr, &mov->dest.dest,
-                        phi->dest.ssa.num_components, phi->dest.ssa.bit_size,
-                        phi->dest.ssa.name);
-      nir_instr_insert(nir_after_instr(&phi->instr), &mov->instr);
+      b.cursor = nir_after_instr(&phi->instr);
+      nir_ssa_def *def = nir_load_reg(&b, reg);
 
-      nir_ssa_def_rewrite_uses(&phi->dest.ssa,
-                               nir_src_for_ssa(&mov->dest.dest.ssa));
+      nir_ssa_def_rewrite_uses(&phi->dest.ssa, nir_src_for_ssa(def));
 
       nir_foreach_phi_src(src, phi) {
          assert(src->src.is_ssa);
-         place_phi_read(shader, reg, src->src.ssa, src->pred, 0);
+         place_phi_read(&b, reg, src->src.ssa, src->pred, 0);
       }
 
       nir_instr_remove(&phi->instr);