Mesa (main): nir/unsigned_upper_bound: don't require dominance metadata

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Module: Mesa
Branch: main
Commit: 49add985ffbfdc44d5865f04ebcb05dbabb88a51
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=49add985ffbfdc44d5865f04ebcb05dbabb88a51

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Wed Mar 24 14:56:48 2021 +0000

nir/unsigned_upper_bound: don't require dominance metadata

Instead, determine if it's a merge or loop exit phi.

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Daniel Schürmann <daniel at schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9808>

---

 src/amd/compiler/aco_instruction_selection_setup.cpp |  4 +---
 src/compiler/nir/nir_opt_offsets.c                   |  3 ---
 src/compiler/nir/nir_range_analysis.c                | 10 ++--------
 3 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/src/amd/compiler/aco_instruction_selection_setup.cpp b/src/amd/compiler/aco_instruction_selection_setup.cpp
index ba36c56e9a3..ba64a736a57 100644
--- a/src/amd/compiler/aco_instruction_selection_setup.cpp
+++ b/src/amd/compiler/aco_instruction_selection_setup.cpp
@@ -303,8 +303,6 @@ void apply_nuw_to_ssa(isel_context *ctx, nir_ssa_def *ssa)
 
 void apply_nuw_to_offsets(isel_context *ctx, nir_function_impl *impl)
 {
-   nir_metadata_require(impl, nir_metadata_dominance);
-
    nir_foreach_block(block, impl) {
       nir_foreach_instr(instr, block) {
          if (instr->type != nir_instr_type_intrinsic)
@@ -594,7 +592,7 @@ void init_context(isel_context *ctx, nir_shader *shader)
    nir_metadata_preserve(impl, nir_metadata_none);
 
    /* we'll need these for isel */
-   nir_metadata_require(impl, nir_metadata_block_index | nir_metadata_dominance);
+   nir_metadata_require(impl, nir_metadata_block_index);
 
    if (!ctx->stage.has(SWStage::GSCopy) && ctx->options->dump_preoptir) {
       fprintf(stderr, "NIR shader before instruction selection:\n");
diff --git a/src/compiler/nir/nir_opt_offsets.c b/src/compiler/nir/nir_opt_offsets.c
index 4047ee5daae..88b7b2a2862 100644
--- a/src/compiler/nir/nir_opt_offsets.c
+++ b/src/compiler/nir/nir_opt_offsets.c
@@ -51,9 +51,6 @@ try_extract_const_addition(nir_builder *b, nir_instr *instr, opt_offsets_state *
          state->range_ht = _mesa_pointer_hash_table_create(NULL);
       }
 
-      /* Dominance metadata is needed by nir_unsigned_upper_bound to chase phis */
-      nir_metadata_require(b->impl, nir_metadata_dominance);
-
       /* Check if there can really be an unsigned wrap. */
       nir_ssa_scalar src0 = {alu->src[0].src.ssa, 0};
       nir_ssa_scalar src1 = {alu->src[1].src.ssa, 0};
diff --git a/src/compiler/nir/nir_range_analysis.c b/src/compiler/nir/nir_range_analysis.c
index 1d7eb99283e..6936b49c9de 100644
--- a/src/compiler/nir/nir_range_analysis.c
+++ b/src/compiler/nir/nir_range_analysis.c
@@ -1402,16 +1402,10 @@ nir_unsigned_upper_bound(nir_shader *shader, struct hash_table *range_ht,
    }
 
    if (scalar.def->parent_instr->type == nir_instr_type_phi) {
-      bool cyclic = false;
-      nir_foreach_phi_src(src, nir_instr_as_phi(scalar.def->parent_instr)) {
-         if (nir_block_dominates(scalar.def->parent_instr->block, src->pred)) {
-            cyclic = true;
-            break;
-         }
-      }
+      nir_cf_node *prev = nir_cf_node_prev(&scalar.def->parent_instr->block->cf_node);
 
       uint32_t res = 0;
-      if (cyclic) {
+      if (!prev || prev->type == nir_cf_node_block) {
          _mesa_hash_table_insert(range_ht, key, (void*)(uintptr_t)max);
 
          struct set *visited = _mesa_pointer_set_create(NULL);