i965: Use ~0 to represent true on all generations.

Jason realized that we could fix the result of the CMP instruction on
Gen <= 5 by doing -(result & 1). Also do the resolves in the vec4
backend before use, rather than when the bool was created. The FS does
this and it saves some unnecessary resolves.

On Ironlake:

total instructions in shared programs: 4289762 -> 4287277 (-0.06%)
instructions in affected programs:     619430 -> 616945 (-0.40%)

Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>

5 files changed, 120 insertions, 102 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 5830b6e..ee9684b 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -516,18 +516,10 @@ brw_initialize_context_constants(struct brw_context *brw)
     *    contains meaning [sic] data, software should make sure all higher bits
     *    are masked out (e.g. by 'and-ing' an [sic] 0x01 constant)."
     *
-    * We select the representation of a true boolean uniform to match what the
-    * CMP instruction returns.
-    *
-    * The Sandybridge BSpec's description of the CMP instruction matches that
-    * of the Ivybridge PRM. (The description in the Sandybridge PRM is seems
-    * to have not been updated from Ironlake). Its CMP instruction behaves like
-    * Ivybridge and newer.
+    * We select the representation of a true boolean uniform to be ~0, and fix
+    * the results of Gen <= 5 CMP instruction's with -(result & 1).
     */
-   if (brw->gen >= 6)
-      ctx->Const.UniformBooleanTrue = ~0;
-   else
-      ctx->Const.UniformBooleanTrue = 1;
+   ctx->Const.UniformBooleanTrue = ~0;
 
    /* From the gen4 PRM, volume 4 page 127:
     *
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index c6cd73b..37857e9 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1399,15 +1399,12 @@ fs_visitor::emit_frontfacing_interpolation()
        * instruction only operates on UD (or D with an abs source modifier)
        * sources without negation.
        *
-       * Instead, use ASR (which will give ~0/true or 0/false) followed by an
-       * AND 1.
+       * Instead, use ASR (which will give ~0/true or 0/false).
        */
-      fs_reg asr = fs_reg(this, glsl_type::bool_type);
       fs_reg g1_6 = fs_reg(retype(brw_vec1_grf(1, 6), BRW_REGISTER_TYPE_D));
       g1_6.negate = true;
 
-      emit(ASR(asr, g1_6, fs_reg(31)));
-      emit(AND(*reg, asr, fs_reg(1)));
+      emit(ASR(*reg, g1_6, fs_reg(31)));
    }
 
    return reg;
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 13673ca..e4296ce 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -535,11 +535,7 @@ fs_visitor::visit(ir_expression *ir)
 
    switch (ir->operation) {
    case ir_unop_logic_not:
-      if (ctx->Const.UniformBooleanTrue != 1) {
-         emit(NOT(this->result, op[0]));
-      } else {
-         emit(XOR(this->result, op[0], fs_reg(1)));
-      }
+      emit(NOT(this->result, op[0]));
       break;
    case ir_unop_neg:
       op[0].negate = !op[0].negate;
@@ -745,7 +741,7 @@ fs_visitor::visit(ir_expression *ir)
    case ir_binop_all_equal:
    case ir_binop_nequal:
    case ir_binop_any_nequal:
-      if (ctx->Const.UniformBooleanTrue == 1) {
+      if (brw->gen <= 5) {
          resolve_bool_comparison(ir->operands[0], &op[0]);
          resolve_bool_comparison(ir->operands[1], &op[1]);
       }
@@ -819,16 +815,13 @@ fs_visitor::visit(ir_expression *ir)
       emit(AND(this->result, op[0], fs_reg(1)));
       break;
    case ir_unop_b2f:
-      if (ctx->Const.UniformBooleanTrue != 1) {
-         op[0].type = BRW_REGISTER_TYPE_D;
-         this->result.type = BRW_REGISTER_TYPE_D;
-         emit(AND(this->result, op[0], fs_reg(0x3f800000u)));
-         this->result.type = BRW_REGISTER_TYPE_F;
-      } else {
-         temp = fs_reg(this, glsl_type::int_type);
-         emit(AND(temp, op[0], fs_reg(1)));
-         emit(MOV(this->result, temp));
+      if (brw->gen <= 5) {
+         resolve_bool_comparison(ir->operands[0], &op[0]);
       }
+      op[0].type = BRW_REGISTER_TYPE_D;
+      this->result.type = BRW_REGISTER_TYPE_D;
+      emit(AND(this->result, op[0], fs_reg(0x3f800000u)));
+      this->result.type = BRW_REGISTER_TYPE_F;
       break;
 
    case ir_unop_f2b:
@@ -2394,39 +2387,36 @@ fs_visitor::emit_bool_to_cond_code(ir_rvalue *ir)
       break;
 
    case ir_binop_logic_xor:
-      if (ctx->Const.UniformBooleanTrue == 1) {
-         fs_reg dst = fs_reg(this, glsl_type::uint_type);
-         emit(XOR(dst, op[0], op[1]));
-         inst = emit(AND(reg_null_d, dst, fs_reg(1)));
-         inst->conditional_mod = BRW_CONDITIONAL_NZ;
+      if (brw->gen <= 5) {
+         fs_reg temp = fs_reg(this, ir->type);
+         emit(XOR(temp, op[0], op[1]));
+         inst = emit(AND(reg_null_d, temp, fs_reg(1)));
       } else {
          inst = emit(XOR(reg_null_d, op[0], op[1]));
-         inst->conditional_mod = BRW_CONDITIONAL_NZ;
       }
+      inst->conditional_mod = BRW_CONDITIONAL_NZ;
       break;
 
    case ir_binop_logic_or:
-      if (ctx->Const.UniformBooleanTrue == 1) {
-         fs_reg dst = fs_reg(this, glsl_type::uint_type);
-         emit(OR(dst, op[0], op[1]));
-         inst = emit(AND(reg_null_d, dst, fs_reg(1)));
-         inst->conditional_mod = BRW_CONDITIONAL_NZ;
+      if (brw->gen <= 5) {
+         fs_reg temp = fs_reg(this, ir->type);
+         emit(OR(temp, op[0], op[1]));
+         inst = emit(AND(reg_null_d, temp, fs_reg(1)));
       } else {
          inst = emit(OR(reg_null_d, op[0], op[1]));
-         inst->conditional_mod = BRW_CONDITIONAL_NZ;
       }
+      inst->conditional_mod = BRW_CONDITIONAL_NZ;
       break;
 
    case ir_binop_logic_and:
-      if (ctx->Const.UniformBooleanTrue == 1) {
-         fs_reg dst = fs_reg(this, glsl_type::uint_type);
-         emit(AND(dst, op[0], op[1]));
-         inst = emit(AND(reg_null_d, dst, fs_reg(1)));
-         inst->conditional_mod = BRW_CONDITIONAL_NZ;
+      if (brw->gen <= 5) {
+         fs_reg temp = fs_reg(this, ir->type);
+         emit(AND(temp, op[0], op[1]));
+         inst = emit(AND(reg_null_d, temp, fs_reg(1)));
       } else {
          inst = emit(AND(reg_null_d, op[0], op[1]));
-         inst->conditional_mod = BRW_CONDITIONAL_NZ;
       }
+      inst->conditional_mod = BRW_CONDITIONAL_NZ;
       break;
 
    case ir_unop_f2b:
@@ -2455,7 +2445,7 @@ fs_visitor::emit_bool_to_cond_code(ir_rvalue *ir)
    case ir_binop_all_equal:
    case ir_binop_nequal:
    case ir_binop_any_nequal:
-      if (ctx->Const.UniformBooleanTrue == 1) {
+      if (brw->gen <= 5) {
          resolve_bool_comparison(expr->operands[0], &op[0]);
          resolve_bool_comparison(expr->operands[1], &op[1]);
       }
@@ -2545,7 +2535,7 @@ fs_visitor::emit_if_gen6(ir_if *ir)
       case ir_binop_all_equal:
       case ir_binop_nequal:
       case ir_binop_any_nequal:
-         if (ctx->Const.UniformBooleanTrue == 1) {
+         if (brw->gen <= 5) {
             resolve_bool_comparison(expr->operands[0], &op[0]);
             resolve_bool_comparison(expr->operands[1], &op[1]);
          }
@@ -3412,17 +3402,25 @@ fs_visitor::resolve_ud_negate(fs_reg *reg)
    *reg = temp;
 }
 
+/**
+ * Resolve the result of a Gen4-5 CMP instruction to a proper boolean.
+ *
+ * CMP on Gen4-5 only sets the LSB of the result; the rest are undefined.
+ * If we need a proper boolean value, we have to fix it up to be 0 or ~0.
+ */
 void
 fs_visitor::resolve_bool_comparison(ir_rvalue *rvalue, fs_reg *reg)
 {
-   assert(ctx->Const.UniformBooleanTrue == 1);
+   assert(brw->gen <= 5);
 
    if (rvalue->type != glsl_type::bool_type)
       return;
 
-   fs_reg temp = fs_reg(this, glsl_type::bool_type);
-   emit(AND(temp, *reg, fs_reg(1)));
-   *reg = temp;
+   fs_reg and_result = fs_reg(this, glsl_type::bool_type);
+   fs_reg neg_result = fs_reg(this, glsl_type::bool_type);
+   emit(AND(and_result, *reg, fs_reg(1)));
+   emit(MOV(neg_result, negate(and_result)));
+   *reg = neg_result;
 }
 
 fs_visitor::fs_visitor(struct brw_context *brw,
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index d94c323..5270027 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -535,6 +535,7 @@ public:
    bool try_emit_mad(ir_expression *ir);
    bool try_emit_b2f_of_compare(ir_expression *ir);
    void resolve_ud_negate(src_reg *reg);
+   void resolve_bool_comparison(ir_rvalue *rvalue, src_reg *reg);
 
    src_reg get_timestamp();
 
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index a2c05ed..73fff75 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -819,18 +819,36 @@ vec4_visitor::emit_bool_to_cond_code(ir_rvalue *ir,
 	 break;
 
       case ir_binop_logic_xor:
-	 inst = emit(XOR(dst_null_d(), op[0], op[1]));
-	 inst->conditional_mod = BRW_CONDITIONAL_NZ;
+         if (brw->gen <= 5) {
+            src_reg temp = src_reg(this, ir->type);
+            emit(XOR(dst_reg(temp), op[0], op[1]));
+            inst = emit(AND(dst_null_d(), temp, src_reg(1)));
+         } else {
+            inst = emit(XOR(dst_null_d(), op[0], op[1]));
+         }
+         inst->conditional_mod = BRW_CONDITIONAL_NZ;
 	 break;
 
       case ir_binop_logic_or:
-	 inst = emit(OR(dst_null_d(), op[0], op[1]));
-	 inst->conditional_mod = BRW_CONDITIONAL_NZ;
+         if (brw->gen <= 5) {
+            src_reg temp = src_reg(this, ir->type);
+            emit(OR(dst_reg(temp), op[0], op[1]));
+            inst = emit(AND(dst_null_d(), temp, src_reg(1)));
+         } else {
+            inst = emit(OR(dst_null_d(), op[0], op[1]));
+         }
+         inst->conditional_mod = BRW_CONDITIONAL_NZ;
 	 break;
 
       case ir_binop_logic_and:
-	 inst = emit(AND(dst_null_d(), op[0], op[1]));
-	 inst->conditional_mod = BRW_CONDITIONAL_NZ;
+         if (brw->gen <= 5) {
+            src_reg temp = src_reg(this, ir->type);
+            emit(AND(dst_reg(temp), op[0], op[1]));
+            inst = emit(AND(dst_null_d(), temp, src_reg(1)));
+         } else {
+            inst = emit(AND(dst_null_d(), op[0], op[1]));
+         }
+         inst->conditional_mod = BRW_CONDITIONAL_NZ;
 	 break;
 
       case ir_unop_f2b:
@@ -852,16 +870,27 @@ vec4_visitor::emit_bool_to_cond_code(ir_rvalue *ir,
 	 break;
 
       case ir_binop_all_equal:
+         if (brw->gen <= 5) {
+            resolve_bool_comparison(expr->operands[0], &op[0]);
+            resolve_bool_comparison(expr->operands[1], &op[1]);
+         }
 	 inst = emit(CMP(dst_null_d(), op[0], op[1], BRW_CONDITIONAL_Z));
 	 *predicate = BRW_PREDICATE_ALIGN16_ALL4H;
 	 break;
 
       case ir_binop_any_nequal:
+         if (brw->gen <= 5) {
+            resolve_bool_comparison(expr->operands[0], &op[0]);
+            resolve_bool_comparison(expr->operands[1], &op[1]);
+         }
 	 inst = emit(CMP(dst_null_d(), op[0], op[1], BRW_CONDITIONAL_NZ));
 	 *predicate = BRW_PREDICATE_ALIGN16_ANY4H;
 	 break;
 
       case ir_unop_any:
+         if (brw->gen <= 5) {
+            resolve_bool_comparison(expr->operands[0], &op[0]);
+         }
 	 inst = emit(CMP(dst_null_d(), op[0], src_reg(0), BRW_CONDITIONAL_NZ));
 	 *predicate = BRW_PREDICATE_ALIGN16_ANY4H;
 	 break;
@@ -872,6 +901,10 @@ vec4_visitor::emit_bool_to_cond_code(ir_rvalue *ir,
       case ir_binop_lequal:
       case ir_binop_equal:
       case ir_binop_nequal:
+         if (brw->gen <= 5) {
+            resolve_bool_comparison(expr->operands[0], &op[0]);
+            resolve_bool_comparison(expr->operands[1], &op[1]);
+         }
 	 emit(CMP(dst_null_d(), op[0], op[1],
 		  brw_conditional_for_comparison(expr->operation)));
 	 break;
@@ -902,14 +935,8 @@ vec4_visitor::emit_bool_to_cond_code(ir_rvalue *ir,
 
    resolve_ud_negate(&this->result);
 
-   if (brw->gen >= 6) {
-      vec4_instruction *inst = emit(AND(dst_null_d(),
-					this->result, src_reg(1)));
-      inst->conditional_mod = BRW_CONDITIONAL_NZ;
-   } else {
-      vec4_instruction *inst = emit(MOV(dst_null_d(), this->result));
-      inst->conditional_mod = BRW_CONDITIONAL_NZ;
-   }
+   vec4_instruction *inst = emit(AND(dst_null_d(), this->result, src_reg(1)));
+   inst->conditional_mod = BRW_CONDITIONAL_NZ;
 }
 
 /**
@@ -1322,11 +1349,7 @@ vec4_visitor::visit(ir_expression *ir)
 
    switch (ir->operation) {
    case ir_unop_logic_not:
-      if (ctx->Const.UniformBooleanTrue != 1) {
-         emit(NOT(result_dst, op[0]));
-      } else {
-         emit(XOR(result_dst, op[0], src_reg(1)));
-      }
+      emit(NOT(result_dst, op[0]));
       break;
    case ir_unop_neg:
       op[0].negate = !op[0].negate;
@@ -1512,11 +1535,12 @@ vec4_visitor::visit(ir_expression *ir)
    case ir_binop_gequal:
    case ir_binop_equal:
    case ir_binop_nequal: {
+      if (brw->gen <= 5) {
+         resolve_bool_comparison(ir->operands[0], &op[0]);
+         resolve_bool_comparison(ir->operands[1], &op[1]);
+      }
       emit(CMP(result_dst, op[0], op[1],
 	       brw_conditional_for_comparison(ir->operation)));
-      if (ctx->Const.UniformBooleanTrue == 1) {
-         emit(AND(result_dst, result_src, src_reg(1)));
-      }
       break;
    }
 
@@ -1530,9 +1554,6 @@ vec4_visitor::visit(ir_expression *ir)
 	 inst->predicate = BRW_PREDICATE_ALIGN16_ALL4H;
       } else {
 	 emit(CMP(result_dst, op[0], op[1], BRW_CONDITIONAL_Z));
-         if (ctx->Const.UniformBooleanTrue == 1) {
-            emit(AND(result_dst, result_src, src_reg(1)));
-         }
       }
       break;
    case ir_binop_any_nequal:
@@ -1546,9 +1567,6 @@ vec4_visitor::visit(ir_expression *ir)
 	 inst->predicate = BRW_PREDICATE_ALIGN16_ANY4H;
       } else {
 	 emit(CMP(result_dst, op[0], op[1], BRW_CONDITIONAL_NZ));
-         if (ctx->Const.UniformBooleanTrue == 1) {
-            emit(AND(result_dst, result_src, src_reg(1)));
-         }
       }
       break;
 
@@ -1610,28 +1628,22 @@ vec4_visitor::visit(ir_expression *ir)
       emit(MOV(result_dst, op[0]));
       break;
    case ir_unop_b2i:
-      if (ctx->Const.UniformBooleanTrue != 1) {
-         emit(AND(result_dst, op[0], src_reg(1)));
-      } else {
-         emit(MOV(result_dst, op[0]));
-      }
+      emit(AND(result_dst, op[0], src_reg(1)));
       break;
    case ir_unop_b2f:
-      if (ctx->Const.UniformBooleanTrue != 1) {
-         op[0].type = BRW_REGISTER_TYPE_D;
-         result_dst.type = BRW_REGISTER_TYPE_D;
-         emit(AND(result_dst, op[0], src_reg(0x3f800000u)));
-         result_dst.type = BRW_REGISTER_TYPE_F;
-      } else {
-         emit(MOV(result_dst, op[0]));
+      if (brw->gen <= 5) {
+         resolve_bool_comparison(ir->operands[0], &op[0]);
       }
+      op[0].type = BRW_REGISTER_TYPE_D;
+      result_dst.type = BRW_REGISTER_TYPE_D;
+      emit(AND(result_dst, op[0], src_reg(0x3f800000u)));
+      result_dst.type = BRW_REGISTER_TYPE_F;
       break;
    case ir_unop_f2b:
-   case ir_unop_i2b:
       emit(CMP(result_dst, op[0], src_reg(0.0f), BRW_CONDITIONAL_NZ));
-      if (ctx->Const.UniformBooleanTrue == 1) {
-         emit(AND(result_dst, result_src, src_reg(1)));
-      }
+      break;
+   case ir_unop_i2b:
+      emit(AND(result_dst, op[0], src_reg(1)));
       break;
 
    case ir_unop_trunc:
@@ -1777,9 +1789,6 @@ vec4_visitor::visit(ir_expression *ir)
       if (ir->type->base_type == GLSL_TYPE_BOOL) {
          emit(CMP(result_dst, packed_consts, src_reg(0u),
                   BRW_CONDITIONAL_NZ));
-         if (ctx->Const.UniformBooleanTrue == 1) {
-            emit(AND(result_dst, result, src_reg(1)));
-         }
       } else {
          emit(MOV(result_dst, packed_consts));
       }
@@ -3535,6 +3544,27 @@ vec4_visitor::resolve_ud_negate(src_reg *reg)
    *reg = temp;
 }
 
+/**
+ * Resolve the result of a Gen4-5 CMP instruction to a proper boolean.
+ *
+ * CMP on Gen4-5 only sets the LSB of the result; the rest are undefined.
+ * If we need a proper boolean value, we have to fix it up to be 0 or ~0.
+ */
+void
+vec4_visitor::resolve_bool_comparison(ir_rvalue *rvalue, src_reg *reg)
+{
+   assert(brw->gen <= 5);
+
+   if (!rvalue->type->is_boolean())
+      return;
+
+   src_reg and_result = src_reg(this, rvalue->type);
+   src_reg neg_result = src_reg(this, rvalue->type);
+   emit(AND(dst_reg(and_result), *reg, src_reg(1)));
+   emit(MOV(dst_reg(neg_result), negate(and_result)));
+   *reg = neg_result;
+}
+
 vec4_visitor::vec4_visitor(struct brw_context *brw,
                            struct brw_vec4_compile *c,
                            struct gl_program *prog,