util: Move _mesa_fsl/util_last_bit into util/bitscan.h

As requested with the initial creation of util/bitscan.h
now move other bitscan related functions into util.

v2: Split into two patches.

Signed-off-by: Mathias Fröhlich <Mathias.Froehlich@web.de>
Tested-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/compiler/glsl/glsl_to_nir.cpp

@@ -146,7 +146,7 @@ glsl_to_nir(const struct gl_shader_program *shader_prog,
    shader->info.name = ralloc_asprintf(shader, "GLSL%d", shader_prog->Name);
    if (shader_prog->Label)
       shader->info.label = ralloc_strdup(shader, shader_prog->Label);
-   shader->info.num_textures = _mesa_fls(sh->Program->SamplersUsed);
+   shader->info.num_textures = util_last_bit(sh->Program->SamplersUsed);
    shader->info.num_ubos = sh->NumUniformBlocks;
    shader->info.num_abos = shader_prog->NumAtomicBuffers;
    shader->info.num_ssbos = sh->NumShaderStorageBlocks;

src/gallium/auxiliary/util/u_math.h

@@ -346,70 +346,6 @@ util_half_inf_sign(int16_t x)
 }
 
 
-/**
- * Find last bit set in a word.  The least significant bit is 1.
- * Return 0 if no bits are set.
- */
-static inline unsigned
-util_last_bit(unsigned u)
-{
-#if defined(HAVE___BUILTIN_CLZ)
-   return u == 0 ? 0 : 32 - __builtin_clz(u);
-#else
-   unsigned r = 0;
-   while (u) {
-       r++;
-       u >>= 1;
-   }
-   return r;
-#endif
-}
-
-/**
- * Find last bit set in a word.  The least significant bit is 1.
- * Return 0 if no bits are set.
- */
-static inline unsigned
-util_last_bit64(uint64_t u)
-{
-#if defined(HAVE___BUILTIN_CLZLL)
-   return u == 0 ? 0 : 64 - __builtin_clzll(u);
-#else
-   unsigned r = 0;
-   while (u) {
-       r++;
-       u >>= 1;
-   }
-   return r;
-#endif
-}
-
-/**
- * Find last bit in a word that does not match the sign bit. The least
- * significant bit is 1.
- * Return 0 if no bits are set.
- */
-static inline unsigned
-util_last_bit_signed(int i)
-{
-   if (i >= 0)
-      return util_last_bit(i);
-   else
-      return util_last_bit(~(unsigned)i);
-}
-
-/* Returns a bitfield in which the first count bits starting at start are
- * set.
- */
-static inline unsigned
-u_bit_consecutive(unsigned start, unsigned count)
-{
-   assert(start + count <= 32);
-   if (count == 32)
-      return ~0;
-   return ((1u << count) - 1) << start;
-}
-
 /**
  * Return float bits.
  */

src/mesa/drivers/dri/i965/brw_cs.c

@@ -220,7 +220,7 @@ brw_upload_cs_prog(struct brw_context *brw)
       return;
 
    brw->cs.base.sampler_count =
-      _mesa_fls(ctx->ComputeProgram._Current->Base.SamplersUsed);
+      util_last_bit(ctx->ComputeProgram._Current->Base.SamplersUsed);
 
    brw_cs_populate_key(brw, &key);
 

src/mesa/drivers/dri/i965/brw_draw.c

@@ -452,15 +452,15 @@ brw_try_draw_prims(struct gl_context *ctx,
     * index.
     */
    brw->wm.base.sampler_count =
-      _mesa_fls(ctx->FragmentProgram._Current->Base.SamplersUsed);
+      util_last_bit(ctx->FragmentProgram._Current->Base.SamplersUsed);
    brw->gs.base.sampler_count = ctx->GeometryProgram._Current ?
-      _mesa_fls(ctx->GeometryProgram._Current->Base.SamplersUsed) : 0;
+      util_last_bit(ctx->GeometryProgram._Current->Base.SamplersUsed) : 0;
    brw->tes.base.sampler_count = ctx->TessEvalProgram._Current ?
-      _mesa_fls(ctx->TessEvalProgram._Current->Base.SamplersUsed) : 0;
+      util_last_bit(ctx->TessEvalProgram._Current->Base.SamplersUsed) : 0;
    brw->tcs.base.sampler_count = ctx->TessCtrlProgram._Current ?
-      _mesa_fls(ctx->TessCtrlProgram._Current->Base.SamplersUsed) : 0;
+      util_last_bit(ctx->TessCtrlProgram._Current->Base.SamplersUsed) : 0;
    brw->vs.base.sampler_count =
-      _mesa_fls(ctx->VertexProgram._Current->Base.SamplersUsed);
+      util_last_bit(ctx->VertexProgram._Current->Base.SamplersUsed);
 
    intel_prepare_render(brw);
    brw_predraw_set_aux_buffers(brw);

src/mesa/drivers/dri/i965/brw_fs_nir.cpp

@@ -1845,7 +1845,7 @@ fs_visitor::emit_gs_control_data_bits(const fs_reg &vertex_count)
       fs_reg prev_count = bld.vgrf(BRW_REGISTER_TYPE_UD, 1);
       abld.ADD(prev_count, vertex_count, brw_imm_ud(0xffffffffu));
       unsigned log2_bits_per_vertex =
-         _mesa_fls(gs_compile->control_data_bits_per_vertex);
+         util_last_bit(gs_compile->control_data_bits_per_vertex);
       abld.SHR(dword_index, prev_count, brw_imm_ud(6u - log2_bits_per_vertex));
 
       if (per_slot_offset.file != BAD_FILE) {
@@ -2789,7 +2789,7 @@ fs_visitor::nir_emit_tcs_intrinsic(const fs_builder &bld,
       if (mask == 0)
          break;
 
-      unsigned num_components = _mesa_fls(mask);
+      unsigned num_components = util_last_bit(mask);
       enum opcode opcode;
 
       /* We can only pack two 64-bit components in a single message, so send
@@ -4523,7 +4523,7 @@ fs_visitor::nir_emit_texture(const fs_builder &bld, nir_tex_instr *instr)
                             nir_ssa_def_components_read(&instr->dest.ssa):
                             (1 << dest_size) - 1;
       assert(write_mask != 0); /* dead code should have been eliminated */
-      inst->regs_written = _mesa_fls(write_mask) * dispatch_width / 8;
+      inst->regs_written = util_last_bit(write_mask) * dispatch_width / 8;
    } else {
       inst->regs_written = 4 * dispatch_width / 8;
    }

src/mesa/drivers/dri/i965/brw_program.c

@@ -674,7 +674,7 @@ brw_setup_tex_for_precompile(struct brw_context *brw,
                              struct gl_program *prog)
 {
    const bool has_shader_channel_select = brw->is_haswell || brw->gen >= 8;
-   unsigned sampler_count = _mesa_fls(prog->SamplersUsed);
+   unsigned sampler_count = util_last_bit(prog->SamplersUsed);
    for (unsigned i = 0; i < sampler_count; i++) {
       if (!has_shader_channel_select && (prog->ShadowSamplers & (1 << i))) {
          /* Assume DEPTH_TEXTURE_MODE is the default: X, X, X, 1 */

src/mesa/drivers/dri/i965/brw_shader.cpp

@@ -1157,7 +1157,7 @@ brw_assign_common_binding_table_offsets(gl_shader_stage stage,
                                         uint32_t next_binding_table_offset)
 {
    const struct gl_linked_shader *shader = NULL;
-   int num_textures = _mesa_fls(prog->SamplersUsed);
+   int num_textures = util_last_bit(prog->SamplersUsed);
 
    if (shader_prog)
       shader = shader_prog->_LinkedShaders[stage];

src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp

@@ -334,7 +334,7 @@ vec4_gs_visitor::emit_control_data_bits()
       emit(ADD(dst_reg(prev_count), this->vertex_count,
                brw_imm_ud(0xffffffffu)));
       unsigned log2_bits_per_vertex =
-         _mesa_fls(c->control_data_bits_per_vertex);
+         util_last_bit(c->control_data_bits_per_vertex);
       emit(SHR(dst_reg(dword_index), prev_count,
                brw_imm_ud(6 - log2_bits_per_vertex)));
    }

src/mesa/drivers/dri/i965/brw_wm_surface_state.c

@@ -998,7 +998,7 @@ update_stage_texture_surfaces(struct brw_context *brw,
    else
       surf_offset += stage_state->prog_data->binding_table.plane_start[plane];
 
-   unsigned num_samplers = _mesa_fls(prog->SamplersUsed);
+   unsigned num_samplers = util_last_bit(prog->SamplersUsed);
    for (unsigned s = 0; s < num_samplers; s++) {
       surf_offset[s] = 0;
 

src/mesa/main/imports.h

@@ -339,51 +339,6 @@ extern unsigned int
 _mesa_bitcount_64(uint64_t n);
 #endif
 
-/**
- * Find the last (most significant) bit set in a word.
- *
- * Essentially ffs() in the reverse direction.
- */
-static inline unsigned int
-_mesa_fls(unsigned int n)
-{
-#ifdef HAVE___BUILTIN_CLZ
-   return n == 0 ? 0 : 32 - __builtin_clz(n);
-#else
-   unsigned int v = 1;
-
-   if (n == 0)
-      return 0;
-
-   while (n >>= 1)
-       v++;
-
-   return v;
-#endif
-}
-
-/**
- * Find the last (most significant) bit set in a uint64_t value.
- *
- * Essentially ffsll() in the reverse direction.
- */
-static inline unsigned int
-_mesa_flsll(uint64_t n)
-{
-#ifdef HAVE___BUILTIN_CLZLL
-   return n == 0 ? 0 : 64 - __builtin_clzll(n);
-#else
-   unsigned int v = 1;
-
-   if (n == 0)
-      return 0;
-
-   while (n >>= 1)
-       v++;
-
-   return v;
-#endif
-}
 
 static inline bool
 _mesa_half_is_negative(GLhalfARB h)

src/mesa/program/prog_to_nir.c

@@ -887,7 +887,7 @@ setup_registers_and_variables(struct ptn_compile *c)
    struct nir_shader *shader = b->shader;
 
    /* Create input variables. */
-   const int num_inputs = _mesa_flsll(c->prog->InputsRead);
+   const int num_inputs = util_last_bit64(c->prog->InputsRead);
    for (int i = 0; i < num_inputs; i++) {
       if (!(c->prog->InputsRead & BITFIELD64_BIT(i)))
          continue;
@@ -948,7 +948,7 @@ setup_registers_and_variables(struct ptn_compile *c)
    }
 
    /* Create output registers and variables. */
-   int max_outputs = _mesa_fls(c->prog->OutputsWritten);
+   int max_outputs = util_last_bit(c->prog->OutputsWritten);
    c->output_regs = rzalloc_array(c, nir_register *, max_outputs);
 
    for (int i = 0; i < max_outputs; i++) {
@@ -1043,7 +1043,7 @@ prog_to_nir(const struct gl_program *prog,
    ptn_add_output_stores(c);
 
    s->info.name = ralloc_asprintf(s, "ARB%d", prog->Id);
-   s->info.num_textures = _mesa_fls(prog->SamplersUsed);
+   s->info.num_textures = util_last_bit(prog->SamplersUsed);
    s->info.num_ubos = 0;
    s->info.num_abos = 0;
    s->info.num_ssbos = 0;

src/util/bitscan.h

@@ -29,6 +29,7 @@
 #ifndef BITSCAN_H
 #define BITSCAN_H
 
+#include <assert.h>
 #include <stdint.h>
 
 #if defined(_MSC_VER)
@@ -146,6 +147,73 @@ u_bit_scan_consecutive_range64(uint64_t *mask, int *start, int *count)
 }
 
 
+/**
+ * Find last bit set in a word.  The least significant bit is 1.
+ * Return 0 if no bits are set.
+ * Essentially ffs() in the reverse direction.
+ */
+static inline unsigned
+util_last_bit(unsigned u)
+{
+#if defined(HAVE___BUILTIN_CLZ)
+   return u == 0 ? 0 : 32 - __builtin_clz(u);
+#else
+   unsigned r = 0;
+   while (u) {
+      r++;
+      u >>= 1;
+   }
+   return r;
+#endif
+}
+
+/**
+ * Find last bit set in a word.  The least significant bit is 1.
+ * Return 0 if no bits are set.
+ * Essentially ffsll() in the reverse direction.
+ */
+static inline unsigned
+util_last_bit64(uint64_t u)
+{
+#if defined(HAVE___BUILTIN_CLZLL)
+   return u == 0 ? 0 : 64 - __builtin_clzll(u);
+#else
+   unsigned r = 0;
+   while (u) {
+      r++;
+      u >>= 1;
+   }
+   return r;
+#endif
+}
+
+/**
+ * Find last bit in a word that does not match the sign bit. The least
+ * significant bit is 1.
+ * Return 0 if no bits are set.
+ */
+static inline unsigned
+util_last_bit_signed(int i)
+{
+   if (i >= 0)
+      return util_last_bit(i);
+   else
+      return util_last_bit(~(unsigned)i);
+}
+
+/* Returns a bitfield in which the first count bits starting at start are
+ * set.
+ */
+static inline unsigned
+u_bit_consecutive(unsigned start, unsigned count)
+{
+   assert(start + count <= 32);
+   if (count == 32)
+      return ~0;
+   return ((1u << count) - 1) << start;
+}
+
+
 #ifdef __cplusplus
 }
 #endif