From 1139ede508579b3abebf4c780691ef4509a3df8d Mon Sep 17 00:00:00 2001
From: Caio Oliveira <caio.oliveira@intel.com>
Date: Fri, 7 Mar 2025 22:08:32 -0800
Subject: [PATCH] brw: Track num_instructions in a block

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34012>
---
 src/intel/compiler/brw_cfg.cpp  | 7 ++++++-
 src/intel/compiler/brw_cfg.h    | 2 ++
 src/intel/compiler/brw_inst.cpp | 6 +++++-
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/intel/compiler/brw_cfg.cpp b/src/intel/compiler/brw_cfg.cpp
index e9cf954df10..be9372a4fea 100644
--- a/src/intel/compiler/brw_cfg.cpp
+++ b/src/intel/compiler/brw_cfg.cpp
@@ -62,7 +62,8 @@ push_stack(exec_list *list, void *mem_ctx, bblock_t *block)
 }
 
 bblock_t::bblock_t(cfg_t *cfg) :
-   cfg(cfg), start_ip(0), end_ip(0), end_ip_delta(0), num(0)
+   cfg(cfg), start_ip(0), end_ip(0), end_ip_delta(0),
+   num_instructions(0), num(0)
 {
    instructions.make_empty();
    parents.make_empty();
@@ -83,6 +84,7 @@ append_inst(bblock_t *block, brw_inst *inst)
    assert(inst->block == NULL);
    inst->block = block;
    block->instructions.push_tail(inst);
+   block->num_instructions++;
 }
 
 cfg_t::cfg_t(brw_shader *s, exec_list *instructions) :
@@ -571,9 +573,12 @@ cfg_t::validate(const char *stage_abbrev)
 
       cfgv_assert(!block->instructions.is_empty());
 
+      unsigned num_instructions = 0;
       foreach_inst_in_block(brw_inst, inst, block) {
          cfgv_assert(block == inst->block);
+         num_instructions++;
       }
+      cfgv_assert(num_instructions == block->num_instructions);
 
       brw_inst *first_inst = block->start();
       if (first_inst->opcode == BRW_OPCODE_DO) {
diff --git a/src/intel/compiler/brw_cfg.h b/src/intel/compiler/brw_cfg.h
index de5125e0ec5..a6ecac96ac2 100644
--- a/src/intel/compiler/brw_cfg.h
+++ b/src/intel/compiler/brw_cfg.h
@@ -105,6 +105,8 @@ struct bblock_t {
     */
    int end_ip_delta;
 
+   unsigned num_instructions;
+
    struct exec_list instructions;
    struct exec_list parents;
    struct exec_list children;
diff --git a/src/intel/compiler/brw_inst.cpp b/src/intel/compiler/brw_inst.cpp
index d3f516c6226..5ffc5878428 100644
--- a/src/intel/compiler/brw_inst.cpp
+++ b/src/intel/compiler/brw_inst.cpp
@@ -982,6 +982,7 @@ brw_inst::insert_before(bblock_t *block, brw_inst *inst)
    exec_node::insert_before(inst);
 
    inst->block = block;
+   inst->block->num_instructions++;
 }
 
 void
@@ -997,6 +998,9 @@ brw_inst::remove(bool defer_later_block_ip_updates)
       return;
    }
 
+   assert(block->num_instructions > 0);
+   block->num_instructions--;
+
    if (defer_later_block_ip_updates) {
       block->end_ip_delta--;
    } else {
@@ -1004,7 +1008,7 @@ brw_inst::remove(bool defer_later_block_ip_updates)
       adjust_later_block_ips(block, -1);
    }
 
-   if (block->start_ip == block->end_ip) {
+   if (block->num_instructions == 0) {
       if (block->end_ip_delta != 0) {
          adjust_later_block_ips(block, block->end_ip_delta);
          block->end_ip_delta = 0;