nir: Turn the format string index into a const index

It is already expected to be constant.

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34208>

src/compiler/nir/nir_functions.c

@@ -410,10 +410,7 @@ lower_calls_vars_instr(struct nir_builder *b,
       if (intrin->intrinsic != nir_intrinsic_printf)
          return false;
 
-      b->cursor = nir_before_instr(instr);
-      nir_src_rewrite(&intrin->src[0],
-                      nir_iadd_imm(b, intrin->src[0].ssa,
-                                   state->printf_index_offset));
+      nir_intrinsic_set_fmt_idx(intrin, nir_intrinsic_fmt_idx(intrin) + state->printf_index_offset);
       break;
    }
    default:

src/compiler/nir/nir_intrinsics.py

@@ -332,6 +332,9 @@ index("unsigned", "repeat_count")
 # coordinates in compute.
 index("bool", "explicit_coord")
 
+# The index of the format string used by a printf. (u_printf_info element of the shader)
+index("unsigned", "fmt_idx")
+
 intrinsic("nop", flags=[CAN_ELIMINATE])
 
 # Uses a value and cannot be eliminated.
@@ -1283,10 +1286,9 @@ intrinsic("load_frag_shading_rate", dest_comp=1, bit_sizes=[32],
 system_value("fully_covered", dest_comp=1, bit_sizes=[1])
 
 # OpenCL printf instruction
-# First source is an index to the format string (u_printf_info element of the shader)
 # Second source is a deref to a struct containing the args
 # Dest is success or failure
-intrinsic("printf", src_comp=[1, 1], dest_comp=1, bit_sizes=[32])
+intrinsic("printf", src_comp=[1], dest_comp=1, bit_sizes=[32], indices=[FMT_IDX])
 # Since most drivers will want to lower to just dumping args
 # in a buffer, nir_lower_printf will do that, but requires
 # the driver to at least provide a base location and size

src/compiler/nir/nir_lower_printf.c

@@ -68,20 +68,19 @@ lower_printf_intrin(nir_builder *b, nir_intrinsic_instr *prntf, void *_options)
       return true;
    }
 
-   nir_def *fmt_str_id = prntf->src[0].ssa;
+   uint32_t fmt_str_id = nir_intrinsic_fmt_idx(prntf);
    if (options->hash_format_strings) {
       /* Rather than store the index of the format string, instead store the
        * hash of the format string itself. This is invariant across shaders
        * which may be more convenient.
        */
-      unsigned idx = nir_src_as_uint(prntf->src[0]) - 1;
-      assert(idx < b->shader->printf_info_count && "must be in-bounds");
+      assert(fmt_str_id - 1 < b->shader->printf_info_count && "must be in-bounds");
 
-      uint32_t hash = u_printf_hash(&b->shader->printf_info[idx]);
-      fmt_str_id = nir_imm_int(b, hash);
+      uint32_t hash = u_printf_hash(&b->shader->printf_info[fmt_str_id - 1]);
+      fmt_str_id = hash;
    }
 
-   nir_deref_instr *args = nir_src_as_deref(prntf->src[1]);
+   nir_deref_instr *args = nir_src_as_deref(prntf->src[0]);
    assert(args->deref_type == nir_deref_type_var);
 
    /* Atomic add a buffer size counter to determine where to write.  If
@@ -94,7 +93,6 @@ lower_printf_intrin(nir_builder *b, nir_intrinsic_instr *prntf, void *_options)
    /* Align the struct size to 4 */
    assert(glsl_type_is_struct_or_ifc(args->type));
    int args_size = align(glsl_get_cl_size(args->type), 4);
-   assert(fmt_str_id->bit_size == 32);
    int fmt_str_id_size = 4;
 
    /* Increment the counter at the beginning of the buffer */
@@ -130,7 +128,7 @@ lower_printf_intrin(nir_builder *b, nir_intrinsic_instr *prntf, void *_options)
                                            nir_var_mem_global,
                                            glsl_uint_type(), 0);
    fmt_str_id_deref->cast.align_mul = 4;
-   nir_store_deref(b, fmt_str_id_deref, fmt_str_id, ~0);
+   nir_store_deref(b, fmt_str_id_deref, nir_imm_int(b, fmt_str_id), ~0);
 
    /* Write the format args */
    for (unsigned i = 0; i < glsl_get_length(args->type); ++i) {

src/compiler/spirv/vtn_opencl.c

@@ -851,8 +851,7 @@ handle_printf(struct vtn_builder *b, uint32_t opcode,
    }
 
    /* Lastly, the actual intrinsic */
-   nir_def *fmt_idx = nir_imm_int(&b->nb, info_idx);
-   nir_def *ret = nir_printf(&b->nb, fmt_idx, &deref_var->def);
+   nir_def *ret = nir_printf(&b->nb, &deref_var->def, .fmt_idx = info_idx);
    vtn_push_nir_ssa(b, w_dest[1], ret);
 
    b->nb.shader->info.uses_printf = true;