nir: Remove nir_alu_dest::saturate

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24432>

src/compiler/nir/nir.c

@@ -530,7 +530,6 @@ nir_alu_dest_copy(nir_alu_dest *dest, const nir_alu_dest *src,
 {
    nir_dest_copy(&dest->dest, &src->dest, &instr->instr);
    dest->write_mask = src->write_mask;
-   dest->saturate = src->saturate;
 }
 
 bool
@@ -693,7 +692,6 @@ static void
 alu_dest_init(nir_alu_dest *dest)
 {
    dest_init(&dest->dest);
-   dest->saturate = false;
    dest->write_mask = 0xf;
 }
 
@@ -2919,15 +2917,14 @@ nir_alu_instr_is_copy(nir_alu_instr *instr)
    assert(instr->src[0].src.is_ssa);
 
    if (instr->op == nir_op_mov) {
-      return !instr->dest.saturate &&
-             !instr->src[0].abs &&
+      return !instr->src[0].abs &&
              !instr->src[0].negate;
    } else if (nir_op_is_vec(instr->op)) {
       for (unsigned i = 0; i < instr->dest.dest.ssa.num_components; i++) {
          if (instr->src[i].abs || instr->src[i].negate)
             return false;
       }
-      return !instr->dest.saturate;
+      return true;
    } else {
       return false;
    }

src/compiler/nir/nir.h

@@ -1219,14 +1219,6 @@ typedef struct {
    /** Base destination */
    nir_dest dest;
 
-   /**
-    * Saturate output modifier
-    *
-    * Only valid for opcodes that output floating-point numbers. Clamps the
-    * output to between 0.0 and 1.0 inclusive.
-    */
-   bool saturate;
-
    /**
     * Write-mask
     *

src/compiler/nir/nir_clone.c

@@ -225,7 +225,6 @@ clone_alu(clone_state *state, const nir_alu_instr *alu)
    nalu->no_unsigned_wrap = alu->no_unsigned_wrap;
 
    __clone_dst(state, &nalu->instr, &nalu->dest.dest, &alu->dest.dest);
-   nalu->dest.saturate = alu->dest.saturate;
    nalu->dest.write_mask = alu->dest.write_mask;
 
    for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; i++) {

src/compiler/nir/nir_loop_analyze.c

@@ -824,9 +824,6 @@ try_eval_const_alu(nir_const_value *dest, nir_alu_instr *alu,
    if (bit_size == 0)
       bit_size = 32;
 
-   /* We shouldn't have any saturate modifiers in the optimization loop. */
-   assert(!alu->dest.saturate);
-
    nir_const_value *srcs[NIR_MAX_VEC_COMPONENTS];
 
    for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; ++i)

src/compiler/nir/nir_lower_alu_width.c

@@ -415,7 +415,6 @@ lower_alu_instr_width(nir_builder *b, nir_instr *instr, void *_data)
       }
 
       nir_alu_ssa_dest_init(lower, components, alu->dest.dest.ssa.bit_size);
-      lower->dest.saturate = alu->dest.saturate;
       lower->exact = alu->exact;
 
       for (i = 0; i < components; i++) {

src/compiler/nir/nir_move_vec_src_uses_to_dest.c

@@ -81,10 +81,6 @@ move_vec_src_uses_to_dest_block(nir_block *block)
       if (!vec->dest.dest.is_ssa)
          continue;
 
-      /* Can't handle saturation */
-      if (vec->dest.saturate)
-         continue;
-
       /* First, mark all of the sources we are going to consider for rewriting
        * to the destination
        */

src/compiler/nir/nir_opt_comparison_pre.c

@@ -258,9 +258,6 @@ comparison_pre_block(nir_block *block, struct block_queue *bq, nir_builder *bld)
       if (alu->dest.dest.ssa.num_components != 1)
          continue;
 
-      if (alu->dest.saturate)
-         continue;
-
       static const uint8_t swizzle[NIR_MAX_VEC_COMPONENTS] = {0};
 
       switch (alu->op) {

src/compiler/nir/nir_opt_constant_folding.c

@@ -83,9 +83,6 @@ try_fold_alu(nir_builder *b, nir_alu_instr *alu)
    if (bit_size == 0)
       bit_size = 32;
 
-   /* We shouldn't have any saturate modifiers in the optimization loop. */
-   assert(!alu->dest.saturate);
-
    nir_const_value dest[NIR_MAX_VEC_COMPONENTS];
    nir_const_value *srcs[NIR_MAX_VEC_COMPONENTS];
    memset(dest, 0, sizeof(dest));

src/compiler/nir/nir_opt_if.c

@@ -1187,7 +1187,6 @@ clone_alu_and_replace_src_defs(nir_builder *b, const nir_alu_instr *alu,
                      alu->dest.dest.ssa.num_components,
                      alu->dest.dest.ssa.bit_size);
 
-   nalu->dest.saturate = alu->dest.saturate;
    nalu->dest.write_mask = alu->dest.write_mask;
 
    for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; i++) {

src/compiler/nir/nir_opt_peephole_select.c

@@ -225,10 +225,6 @@ block_check_for_allowed_instrs(nir_block *block, unsigned *count,
             if (mov->op != nir_op_fsat && !movelike)
                (*count)++;
          } else {
-            /* Can't handle saturate */
-            if (mov->dest.saturate)
-               return false;
-
             /* The only uses of this definition must be phis in the successor */
             nir_foreach_use_including_if(use, &mov->dest.dest.ssa) {
                if (use->is_if ||

src/compiler/nir/nir_print.c

@@ -455,8 +455,6 @@ print_alu_instr(nir_alu_instr *instr, print_state *state)
    fprintf(fp, " = %s", nir_op_infos[instr->op].name);
    if (instr->exact)
       fprintf(fp, "!");
-   if (instr->dest.saturate)
-      fprintf(fp, ".sat");
    if (instr->no_signed_wrap)
       fprintf(fp, ".nsw");
    if (instr->no_unsigned_wrap)

src/compiler/nir/nir_search.c

@@ -381,7 +381,6 @@ match_expression(const nir_algebraic_table *table, const nir_search_expression *
    if (state->inexact_match && state->has_exact_alu)
       return false;
 
-   assert(!instr->dest.saturate);
    assert(nir_op_infos[instr->op].num_inputs > 0);
 
    /* If we have an explicitly sized destination, we can only handle the
@@ -453,7 +452,6 @@ construct_value(nir_builder *build,
       nir_ssa_dest_init(&alu->instr, &alu->dest.dest, num_components,
                         dst_bit_size);
       alu->dest.write_mask = (1 << num_components) - 1;
-      alu->dest.saturate = false;
 
       /* We have no way of knowing what values in a given search expression
        * map to a particular replacement value.  Therefore, if the

src/compiler/nir/nir_serialize.c

@@ -542,7 +542,7 @@ union packed_instr {
       unsigned exact:1;
       unsigned no_signed_wrap:1;
       unsigned no_unsigned_wrap:1;
-      unsigned saturate:1;
+      unsigned padding:1;
       /* Reg: writemask; SSA: swizzles for 2 srcs */
       unsigned writemask_or_two_swizzles:4;
       unsigned op:9;
@@ -731,7 +731,6 @@ write_alu(write_ctx *ctx, const nir_alu_instr *alu)
    header.alu.exact = alu->exact;
    header.alu.no_signed_wrap = alu->no_signed_wrap;
    header.alu.no_unsigned_wrap = alu->no_unsigned_wrap;
-   header.alu.saturate = alu->dest.saturate;
    header.alu.op = alu->op;
    header.alu.packed_src_ssa_16bit = is_alu_src_ssa_16bit(ctx, alu);
 
@@ -796,7 +795,6 @@ read_alu(read_ctx *ctx, union packed_instr header)
    alu->exact = header.alu.exact;
    alu->no_signed_wrap = header.alu.no_signed_wrap;
    alu->no_unsigned_wrap = header.alu.no_unsigned_wrap;
-   alu->dest.saturate = header.alu.saturate;
 
    read_dest(ctx, &alu->dest.dest, &alu->instr, header);
 

src/compiler/nir/nir_validate.c

@@ -222,10 +222,6 @@ static void
 validate_alu_dest(nir_alu_instr *instr, validate_state *state)
 {
    nir_alu_dest *dest = &instr->dest;
-
-   if (instr->op == nir_op_mov)
-      assert(!dest->saturate);
-
    unsigned dest_size = nir_dest_num_components(dest->dest);
    /*
     * validate that the instruction doesn't write to components not in the
@@ -233,15 +229,6 @@ validate_alu_dest(nir_alu_instr *instr, validate_state *state)
     */
    validate_assert(state, !(dest->write_mask & ~nir_component_mask(dest_size)));
 
-   /* validate that saturate is only ever used on instructions with
-    * destinations of type float
-    */
-   nir_alu_instr *alu = nir_instr_as_alu(state->instr);
-   validate_assert(state,
-          (nir_alu_type_get_base_type(nir_op_infos[alu->op].output_type) ==
-           nir_type_float) ||
-          !dest->saturate);
-
    validate_dest(&dest->dest, state, 0, 0);
 }