[Mesa-dev] [PATCH 08/11] i965/vec4: Track the number of channels used in a virtual grf.

[Eric Anholt]

For tracking live variables, we want to know when a register is completely
rewritten, so we need to be able to compare a writemask to the size of the
register.  There's also potential use for this in register coalescing.
---
 src/mesa/drivers/dri/i965/brw_vec4.cpp             |    4 +--
 src/mesa/drivers/dri/i965/brw_vec4.h               |    5 ++-
 .../drivers/dri/i965/brw_vec4_reg_allocate.cpp     |    4 +--
 src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp     |   37 +++++++++++---------
 4 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index 917959d..47a2d58 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -887,9 +887,9 @@ vec4_visitor::split_virtual_grfs()
       if (this->virtual_grf_sizes[i] == 1)
          continue;
 
-      new_virtual_grf[i] = virtual_grf_alloc(1);
+      new_virtual_grf[i] = virtual_grf_alloc(1, this->virtual_grf_chans[i]);
       for (int j = 2; j < this->virtual_grf_sizes[i]; j++) {
-         int reg = virtual_grf_alloc(1);
+         int reg = virtual_grf_alloc(1, this->virtual_grf_chans[i]);
          assert(reg == new_virtual_grf[i] + j - 1);
          (void) reg;
       }
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index 12b2ebe..cd05462 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -226,7 +226,10 @@ public:
    ir_instruction *base_ir;
    const char *current_annotation;
 
+   /** For each virtual grf, the number of contiguous registers it needs */
    int *virtual_grf_sizes;
+   /** For each virtual grf, the number of channels used per register. */
+   int *virtual_grf_chans;
    int virtual_grf_count;
    int virtual_grf_array_size;
    int first_non_payload_grf;
@@ -294,7 +297,7 @@ public:
    bool run(void);
    void fail(const char *msg, ...);
 
-   int virtual_grf_alloc(int size);
+   int virtual_grf_alloc(int size, int chans);
    void setup_uniform_clipplane_values();
    int setup_uniform_values(int loc, const glsl_type *type);
    void setup_builtin_uniform_values(ir_variable *ir);
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
index bad2728..5529794 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
@@ -330,7 +330,7 @@ vec4_visitor::spill_reg(int spill_reg_nr)
       for (unsigned int i = 0; i < 3; i++) {
          if (inst->src[i].file == GRF && inst->src[i].reg == spill_reg_nr) {
             src_reg spill_reg = inst->src[i];
-            inst->src[i].reg = virtual_grf_alloc(1);
+            inst->src[i].reg = virtual_grf_alloc(1, 4);
             dst_reg temp = dst_reg(inst->src[i]);
 
             /* Only read the necessary channels, to avoid overwriting the rest
@@ -347,7 +347,7 @@ vec4_visitor::spill_reg(int spill_reg_nr)
 
       if (inst->dst.file == GRF && inst->dst.reg == spill_reg_nr) {
          dst_reg spill_reg = inst->dst;
-         inst->dst.reg = virtual_grf_alloc(1);
+         inst->dst.reg = virtual_grf_alloc(1, 4);
 
          /* We don't want a swizzle when reading from the source; read the
           * whole register and use spill_reg's writemask to select which
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 59428a1..dba999b 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -402,7 +402,7 @@ type_size(const struct glsl_type *type)
 }
 
 int
-vec4_visitor::virtual_grf_alloc(int size)
+vec4_visitor::virtual_grf_alloc(int size, int chans)
 {
    if (virtual_grf_array_size <= virtual_grf_count) {
       if (virtual_grf_array_size == 0)
@@ -411,12 +411,15 @@ vec4_visitor::virtual_grf_alloc(int size)
 	 virtual_grf_array_size *= 2;
       virtual_grf_sizes = reralloc(mem_ctx, virtual_grf_sizes, int,
 				   virtual_grf_array_size);
+      virtual_grf_chans = reralloc(mem_ctx, virtual_grf_chans, int,
+				   virtual_grf_array_size);
       virtual_grf_reg_map = reralloc(mem_ctx, virtual_grf_reg_map, int,
 				     virtual_grf_array_size);
    }
    virtual_grf_reg_map[virtual_grf_count] = virtual_grf_reg_count;
    virtual_grf_reg_count += size;
    virtual_grf_sizes[virtual_grf_count] = size;
+   virtual_grf_chans[virtual_grf_count] = chans;
    return virtual_grf_count++;
 }
 
@@ -424,15 +427,15 @@ src_reg::src_reg(class vec4_visitor *v, const struct glsl_type *type)
 {
    init();
 
-   this->file = GRF;
-   this->reg = v->virtual_grf_alloc(type_size(type));
-
-   if (type->is_array() || type->is_record()) {
-      this->swizzle = BRW_SWIZZLE_NOOP;
-   } else {
-      this->swizzle = swizzle_for_size(type->vector_elements);
-   }
+   int chans;
+   if (type->is_array() || type->is_record())
+      chans = 4;
+   else
+      chans = type->vector_elements;
 
+   this->file = GRF;
+   this->reg = v->virtual_grf_alloc(type_size(type), chans);
+   this->swizzle = swizzle_for_size(chans);
    this->type = brw_type_for_base_type(type);
 }
 
@@ -440,15 +443,15 @@ dst_reg::dst_reg(class vec4_visitor *v, const struct glsl_type *type)
 {
    init();
 
-   this->file = GRF;
-   this->reg = v->virtual_grf_alloc(type_size(type));
-
-   if (type->is_array() || type->is_record()) {
-      this->writemask = WRITEMASK_XYZW;
-   } else {
-      this->writemask = (1 << type->vector_elements) - 1;
-   }
+   int chans;
+   if (type->is_array() || type->is_record())
+      chans = 4;
+   else
+      chans = type->vector_elements;
 
+   this->file = GRF;
+   this->reg = v->virtual_grf_alloc(type_size(type), chans);
+   this->writemask = (1 << chans) - 1;
    this->type = brw_type_for_base_type(type);
 }
 
-- 
1.7.10.4