util: Add and use util_is_power_of_two_nonzero

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eduardo Lima Mitev <elima@igalia.com>

src/compiler/nir/nir_search_helpers.h

@@ -28,12 +28,7 @@
 #define _NIR_SEARCH_HELPERS_
 
 #include "nir.h"
-
-static inline bool
-__is_power_of_two(unsigned int x)
-{
-   return ((x != 0) && !(x & (x - 1)));
-}
+#include "util/bitscan.h"
 
 static inline bool
 is_pos_power_of_two(nir_alu_instr *instr, unsigned src, unsigned num_components,
@@ -50,11 +45,11 @@ is_pos_power_of_two(nir_alu_instr *instr, unsigned src, unsigned num_components,
       case nir_type_int:
          if (val->i32[swizzle[i]] < 0)
             return false;
-         if (!__is_power_of_two(val->i32[swizzle[i]]))
+         if (!util_is_power_of_two_nonzero(val->i32[swizzle[i]]))
             return false;
          break;
       case nir_type_uint:
-         if (!__is_power_of_two(val->u32[swizzle[i]]))
+         if (!util_is_power_of_two_nonzero(val->u32[swizzle[i]]))
             return false;
          break;
       default:
@@ -80,7 +75,7 @@ is_neg_power_of_two(nir_alu_instr *instr, unsigned src, unsigned num_components,
       case nir_type_int:
          if (val->i32[swizzle[i]] > 0)
             return false;
-         if (!__is_power_of_two(abs(val->i32[swizzle[i]])))
+         if (!util_is_power_of_two_nonzero(abs(val->i32[swizzle[i]])))
             return false;
          break;
       default:

src/compiler/nir/nir_validate.c

@@ -982,7 +982,7 @@ validate_var_decl(nir_variable *var, bool is_global, validate_state *state)
    validate_assert(state, is_global == nir_variable_is_global(var));
 
    /* Must have exactly one mode set */
-   validate_assert(state, util_bitcount(var->data.mode) == 1);
+   validate_assert(state, util_is_power_of_two_nonzero(var->data.mode));
 
    if (var->data.compact) {
       /* The "compact" flag is only valid on arrays of scalars. */

src/gallium/drivers/etnaviv/etnaviv_blt.c

@@ -178,7 +178,7 @@ emit_blt_copyimage(struct etna_cmd_stream *stream, const struct blt_imgcopy_op *
 static void
 emit_blt_inplace(struct etna_cmd_stream *stream, const struct blt_inplace_op *op)
 {
-   assert(op->bpp > 0 && util_is_power_of_two_or_zero(op->bpp));
+   assert(op->bpp > 0 && util_is_power_of_two_nonzero(op->bpp));
    etna_cmd_stream_reserve(stream, 64*2); /* Never allow BLT sequences to be broken up */
    etna_set_state(stream, VIVS_BLT_ENABLE, 0x00000001);
    etna_set_state(stream, VIVS_BLT_CONFIG,

src/intel/compiler/brw_fs.cpp

@@ -1976,7 +1976,7 @@ struct cplx_align {
 static void
 cplx_align_assert_sane(struct cplx_align a)
 {
-   assert(a.mul > 0 && util_is_power_of_two_or_zero(a.mul));
+   assert(a.mul > 0 && util_is_power_of_two_nonzero(a.mul));
    assert(a.offset < a.mul);
 }
 
@@ -2028,7 +2028,7 @@ static void
 mark_uniform_slots_read(struct uniform_slot_info *slots,
                         unsigned num_slots, unsigned alignment)
 {
-   assert(alignment > 0 && util_is_power_of_two_or_zero(alignment));
+   assert(alignment > 0 && util_is_power_of_two_nonzero(alignment));
    assert(alignment <= CPLX_ALIGN_MAX_MUL);
 
    /* We can't align a slot to anything less than the slot size */

src/util/bitscan.h

@@ -119,6 +119,17 @@ util_is_power_of_two_or_zero(unsigned v)
    return (v & (v - 1)) == 0;
 }
 
+/* Determine if an unsigned value is a power of two.
+ *
+ * \note
+ * Zero is \b not treated as a power of two.
+ */
+static inline bool
+util_is_power_of_two_nonzero(unsigned v)
+{
+   return v != 0 && (v & (v - 1)) == 0;
+}
+
 /* For looping over a bitmask when you want to loop over consecutive bits
  * manually, for example:
  *