i965/vs: Add support for bit instructions.

v2: Rebase on LRP addition.
    Use fix_3src_operand() when emitting BFE and BFI2.
    Add BFE and BFI2 to is_3src_inst check in
      brw_vec4_copy_propagation.cpp.
    Subtract result of FBH from 31 (unless an error) to convert
      MSB counts to LSB counts

Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>

diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index 06b0f6a33e18278c4eebef5a1462f37769305d25..7614ac58652c878ccdee8a1a6b1aac1f31755e96 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -375,6 +375,13 @@ public:
    vec4_instruction *SCRATCH_READ(dst_reg dst, src_reg index);
    vec4_instruction *SCRATCH_WRITE(dst_reg dst, src_reg src, src_reg index);
    vec4_instruction *LRP(dst_reg dst, src_reg a, src_reg y, src_reg x);
+   vec4_instruction *BFREV(dst_reg dst, src_reg value);
+   vec4_instruction *BFE(dst_reg dst, src_reg bits, src_reg offset, src_reg value);
+   vec4_instruction *BFI1(dst_reg dst, src_reg bits, src_reg offset);
+   vec4_instruction *BFI2(dst_reg dst, src_reg bfi1_dst, src_reg insert, src_reg base);
+   vec4_instruction *FBH(dst_reg dst, src_reg value);
+   vec4_instruction *FBL(dst_reg dst, src_reg value);
+   vec4_instruction *CBIT(dst_reg dst, src_reg value);
 
    int implied_mrf_writes(vec4_instruction *inst);
 

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
index f2c6cd6091180abad1215522eb4af0c728b3f0ec..39eef4b0d6571edf5c8d75afcb606a5495dfb766 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
@@ -215,7 +215,10 @@ vec4_visitor::try_copy_propagation(struct intel_context *intel,
    if (has_source_modifiers && !can_do_source_mods(inst))
       return false;
 
-   if (inst->opcode == BRW_OPCODE_LRP && value.file == UNIFORM)
+   bool is_3src_inst = (inst->opcode == BRW_OPCODE_LRP ||
+                        inst->opcode == BRW_OPCODE_BFE ||
+                        inst->opcode == BRW_OPCODE_BFI2);
+   if (is_3src_inst && value.file == UNIFORM)
       return false;
 
    /* We can't copy-propagate a UD negation into a condmod

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp b/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp
index 96b4965045b71c2448f30a4588f444e3a4510ea9..91101f29b0d6b4bb1d8fbfe0a6eb00555e2a9e59 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp
@@ -842,6 +842,35 @@ vec4_generator::generate_code(exec_list *instructions)
          brw_LRP(p, dst, src[0], src[1], src[2]);
          break;
 
+      case BRW_OPCODE_BFREV:
+         /* BFREV only supports UD type for src and dst. */
+         brw_BFREV(p, retype(dst, BRW_REGISTER_TYPE_UD),
+                      retype(src[0], BRW_REGISTER_TYPE_UD));
+         break;
+      case BRW_OPCODE_FBH:
+         /* FBH only supports UD type for dst. */
+         brw_FBH(p, retype(dst, BRW_REGISTER_TYPE_UD), src[0]);
+         break;
+      case BRW_OPCODE_FBL:
+         /* FBL only supports UD type for dst. */
+         brw_FBL(p, retype(dst, BRW_REGISTER_TYPE_UD), src[0]);
+         break;
+      case BRW_OPCODE_CBIT:
+         /* CBIT only supports UD type for dst. */
+         brw_CBIT(p, retype(dst, BRW_REGISTER_TYPE_UD), src[0]);
+         break;
+
+      case BRW_OPCODE_BFE:
+         brw_BFE(p, dst, src[0], src[1], src[2]);
+         break;
+
+      case BRW_OPCODE_BFI1:
+         brw_BFI1(p, dst, src[0], src[1]);
+         break;
+      case BRW_OPCODE_BFI2:
+         brw_BFI2(p, dst, src[0], src[1], src[2]);
+         break;
+
       case BRW_OPCODE_IF:
         if (inst->src[0].file != BAD_FILE) {
            /* The instruction has an embedded compare (only allowed on gen6) */

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 3b0687f615a1298070ff0e3b0f7fdd9d2a51842f..cda425efde8117ca2455684eaeeb4eb0f8601540 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -136,6 +136,13 @@ ALU2(SHL)
 ALU2(SHR)
 ALU2(ASR)
 ALU3(LRP)
+ALU1(BFREV)
+ALU3(BFE)
+ALU2(BFI1)
+ALU3(BFI2)
+ALU1(FBH)
+ALU1(FBL)
+ALU1(CBIT)
 
 /** Gen4 predicated IF. */
 vec4_instruction *
@@ -1382,6 +1389,39 @@ vec4_visitor::visit(ir_expression *ir)
       assert(!"derivatives not valid in vertex shader");
       break;
 
+   case ir_unop_bitfield_reverse:
+      emit(BFREV(result_dst, op[0]));
+      break;
+   case ir_unop_bit_count:
+      emit(CBIT(result_dst, op[0]));
+      break;
+   case ir_unop_find_msb: {
+      src_reg temp = src_reg(this, glsl_type::uint_type);
+
+      inst = emit(FBH(dst_reg(temp), op[0]));
+      inst->dst.writemask = WRITEMASK_XYZW;
+
+      /* FBH counts from the MSB side, while GLSL's findMSB() wants the count
+       * from the LSB side. If FBH didn't return an error (0xFFFFFFFF), then
+       * subtract the result from 31 to convert the MSB count into an LSB count.
+       */
+
+      /* FBH only supports UD type for dst, so use a MOV to convert UD to D. */
+      temp.swizzle = BRW_SWIZZLE_NOOP;
+      emit(MOV(result_dst, temp));
+
+      src_reg src_tmp = src_reg(result_dst);
+      emit(CMP(dst_null_d(), src_tmp, src_reg(-1), BRW_CONDITIONAL_NZ));
+
+      src_tmp.negate = true;
+      inst = emit(ADD(result_dst, src_tmp, src_reg(31)));
+      inst->predicate = BRW_PREDICATE_NORMAL;
+      break;
+   }
+   case ir_unop_find_lsb:
+      emit(FBL(result_dst, op[0]));
+      break;
+
    case ir_unop_noise:
       assert(!"not reached: should be handled by lower_noise");
       break;
@@ -1582,6 +1622,10 @@ vec4_visitor::visit(ir_expression *ir)
          inst = emit(SHR(result_dst, op[0], op[1]));
       break;
 
+   case ir_binop_bfm:
+      emit(BFI1(result_dst, op[0], op[1]));
+      break;
+
    case ir_binop_ubo_load: {
       ir_constant *uniform_block = ir->operands[0]->as_constant();
       ir_constant *const_offset_ir = ir->operands[1]->as_constant();
@@ -1637,6 +1681,28 @@ vec4_visitor::visit(ir_expression *ir)
       emit(LRP(result_dst, op[2], op[1], op[0]));
       break;
 
+   case ir_triop_bfi:
+      op[0] = fix_3src_operand(op[0]);
+      op[1] = fix_3src_operand(op[1]);
+      op[2] = fix_3src_operand(op[2]);
+      emit(BFI2(result_dst, op[0], op[1], op[2]));
+      break;
+
+   case ir_triop_bitfield_extract:
+      op[0] = fix_3src_operand(op[0]);
+      op[1] = fix_3src_operand(op[1]);
+      op[2] = fix_3src_operand(op[2]);
+      /* Note that the instruction's argument order is reversed from GLSL
+       * and the IR.
+       */
+      emit(BFE(result_dst, op[2], op[1], op[0]));
+      break;
+
+   case ir_quadop_bitfield_insert:
+      assert(!"not reached: should be handled by "
+              "bitfield_insert_to_bfm_bfi\n");
+      break;
+
    case ir_quadop_vector:
       assert(!"not reached: should be handled by lower_quadop_vector");
       break;