Mesa (main): nir: Delete the per-instr SSA liveness impl.

[GitLab Mirror]

Module: Mesa
Branch: main
Commit: 20469009c7153b154e754446b8e0694610c6d03e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=20469009c7153b154e754446b8e0694610c6d03e

Author: Emma Anholt <emma at anholt.net>
Date:   Mon Jan  3 16:41:07 2022 -0800

nir: Delete the per-instr SSA liveness impl.

It was introduced for nir-to-tgsi, and I found that it was the wrong
approach.  There's a reason nobody else does RA this way.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14404>

---

 src/compiler/nir/nir.h          | 20 ------------
 src/compiler/nir/nir_liveness.c | 71 -----------------------------------------
 2 files changed, 91 deletions(-)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 2837170b13f..bbfd810190c 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -3569,26 +3569,6 @@ nir_shader_get_entrypoint(nir_shader *shader)
    return func->impl;
 }
 
-typedef struct nir_liveness_bounds {
-   uint32_t start;
-   uint32_t end;
-} nir_liveness_bounds;
-
-typedef struct nir_instr_liveness {
-   /**
-    * nir_instr->index for the start and end of a single live interval for SSA
-    * defs.  ssa values last used by a nir_if condition will have an interval
-    * ending at the first instruction after the last one before the if
-    * condition.
-    *
-    * Indexed by def->index (impl->ssa_alloc elements).
-    */
-   struct nir_liveness_bounds *defs;
-} nir_instr_liveness;
-
-nir_instr_liveness *
-nir_live_ssa_defs_per_instr(nir_function_impl *impl);
-
 nir_shader *nir_shader_create(void *mem_ctx,
                               gl_shader_stage stage,
                               const nir_shader_compiler_options *options,
diff --git a/src/compiler/nir/nir_liveness.c b/src/compiler/nir/nir_liveness.c
index 941ed1cfa1d..1e986ff0e41 100644
--- a/src/compiler/nir/nir_liveness.c
+++ b/src/compiler/nir/nir_liveness.c
@@ -342,74 +342,3 @@ nir_ssa_defs_interfere(nir_ssa_def *a, nir_ssa_def *b)
       return nir_ssa_def_is_live_at(b, a->parent_instr);
    }
 }
-
-/* Takes an SSA def's defs and uses and expands the live interval to cover
- * that range.  Control flow effects are handled separately.
- */
-static bool def_cb(nir_ssa_def *def, void *state)
-{
-   nir_instr_liveness *liveness = state;
-   nir_instr *instr = def->parent_instr;
-   int index = def->index;
-
-   liveness->defs[index].start = MIN2(liveness->defs[index].start, instr->index);
-
-   nir_foreach_use(src, def) {
-      liveness->defs[index].end = MAX2(liveness->defs[index].end,
-                                       src->parent_instr->index);
-   }
-
-   return true;
-}
-
-nir_instr_liveness *
-nir_live_ssa_defs_per_instr(nir_function_impl *impl)
-{
-   /* We'll use block-level live_ssa_defs to expand our per-instr ranges for
-    * control flow.
-    */
-   nir_metadata_require(impl,
-                        nir_metadata_block_index |
-                        nir_metadata_instr_index |
-                        nir_metadata_live_ssa_defs);
-
-   /* Make our struct. */
-   nir_instr_liveness *liveness = ralloc(NULL, nir_instr_liveness);
-   liveness->defs = rzalloc_array(liveness, nir_liveness_bounds,
-                                  impl->ssa_alloc);
-
-   /* Set our starts so we can use MIN2() as we accumulate bounds. */
-   for (int i = 0; i < impl->ssa_alloc; i++)
-      liveness->defs->start = ~0;
-
-   nir_foreach_block(block, impl) {
-      unsigned index;
-      BITSET_FOREACH_SET(index, block->live_in, impl->ssa_alloc) {
-         liveness->defs[index].start = MIN2(liveness->defs[index].start,
-                                            block->start_ip);
-      }
-
-      nir_foreach_instr(instr, block) {
-         nir_foreach_ssa_def(instr, def_cb, liveness);
-      };
-
-      /* track an if src's use.  We need to make sure that our value is live
-       * across the if reference, where we don't have an instr->index
-       * representing the use.  Mark it as live through the end of the block.
-       */
-      nir_if *nif = nir_block_get_following_if(block);
-      if (nif) {
-         if (nif->condition.is_ssa) {
-            liveness->defs[nif->condition.ssa->index].end = MAX2(
-               liveness->defs[nif->condition.ssa->index].end, block->end_ip);
-         }
-      }
-
-      BITSET_FOREACH_SET(index, block->live_out, impl->ssa_alloc) {
-         liveness->defs[index].end = MAX2(liveness->defs[index].end,
-                                          block->end_ip);
-      }
-   }
-
-   return liveness;
-}