intel/compiler: Add a INVALID_{,HW_}REG_TYPE macros

Since the enum brw_reg_type is packed, comparisons with -1 don't work
directly, necessitating the cast. Add a macro to avoid this confusion.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/2635>

src/intel/compiler/brw_eu_compact.c

@@ -1512,10 +1512,10 @@ has_immediate(const struct gen_device_info *devinfo, const brw_inst *inst,
 {
    if (brw_inst_src0_reg_file(devinfo, inst) == BRW_IMMEDIATE_VALUE) {
       *type = brw_inst_src0_type(devinfo, inst);
-      return *type != (enum brw_reg_type)-1;
+      return *type != INVALID_REG_TYPE;
    } else if (brw_inst_src1_reg_file(devinfo, inst) == BRW_IMMEDIATE_VALUE) {
       *type = brw_inst_src1_type(devinfo, inst);
-      return *type != (enum brw_reg_type)-1;
+      return *type != INVALID_REG_TYPE;
    }
 
    return false;

src/intel/compiler/brw_reg_type.c

@@ -289,7 +289,7 @@ brw_hw_type_to_reg_type(const struct gen_device_info *devinfo,
          }
       }
    }
-   return (enum brw_reg_type)-1;
+   return INVALID_REG_TYPE;
 }
 
 /**
@@ -339,7 +339,7 @@ brw_a16_hw_3src_type_to_reg_type(const struct gen_device_info *devinfo,
          return i;
       }
    }
-   return (enum brw_reg_type)-1;
+   return INVALID_REG_TYPE;
 }
 
 /**
@@ -359,7 +359,7 @@ brw_a1_hw_3src_type_to_reg_type(const struct gen_device_info *devinfo,
          return i;
       }
    }
-   return (enum brw_reg_type)-1;
+   return INVALID_REG_TYPE;
 }
 
 /**

src/intel/compiler/brw_reg_type.h

@@ -100,6 +100,9 @@ brw_reg_type_is_integer(enum brw_reg_type type)
    }
 }
 
+#define INVALID_REG_TYPE    ((enum brw_reg_type)-1)
+#define INVALID_HW_REG_TYPE ((unsigned)-1)
+
 unsigned
 brw_reg_type_to_hw_type(const struct gen_device_info *devinfo,
                         enum brw_reg_file file, enum brw_reg_type type);