brw: Make brw_range use half-open ranges

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34253>

src/intel/compiler/brw_analysis.cpp

@@ -112,8 +112,7 @@ brw_ip_ranges::validate(const brw_shader *s) const
 
    if (num_blocks) {
       bblock_t *last_block = s->cfg->blocks[num_blocks - 1];
-      unsigned last_ip = range(last_block).end;
-      if (last_ip + 1 != s->cfg->total_instructions)
+      if (range(last_block).end != (int)s->cfg->total_instructions)
          return false;
    }
 
@@ -129,7 +128,7 @@ brw_register_pressure::brw_register_pressure(const brw_shader *v)
 
    for (unsigned reg = 0; reg < v->alloc.count; reg++) {
       brw_range range = live.vgrf_range[reg];
-      for (int ip = range.start; ip <= range.end; ip++)
+      for (int ip = range.start; ip < range.end; ip++)
          regs_live_at_ip[ip] += v->alloc.sizes[reg];
    }
 

src/intel/compiler/brw_analysis.h

@@ -232,7 +232,6 @@ private:
    bblock_t **parents;
 };
 
-/* TODO: Make these exclusive ranges, i.e. half-open at the end. */
 struct brw_range {
    int start;
    int end;
@@ -240,22 +239,22 @@ struct brw_range {
    /* If range not empty, this is the last value inside the range. */
    inline int last() const
    {
-      return end;
+      return end - 1;
    }
 
    inline bool is_empty() const
    {
-      return end < start;
+      return end <= start;
    }
 
    inline int len() const
    {
-      return end - start + 1;
+      return end - start;
    }
 
    inline bool contains(int x) const
    {
-      return start <= x && x <= end;
+      return start <= x && x < end;
    }
 
    inline bool contains(brw_range r) const
@@ -278,15 +277,15 @@ inline brw_range
 merge(brw_range r, int x)
 {
    if (r.is_empty())
-      return { x, x };
-   return { MIN2(r.start, x), MAX2(r.end, x) };
+      return { x, x + 1 };
+   return { MIN2(r.start, x), MAX2(r.end, x + 1) };
 }
 
 inline bool
 overlaps(brw_range a, brw_range b)
 {
-   return a.start <= b.end &&
-          b.start <= a.end;
+   return a.start < b.end &&
+          b.start < a.end;
 }
 
 inline brw_range
@@ -296,10 +295,9 @@ intersect(brw_range a, brw_range b)
       return { MAX2(a.start, b.start),
                MIN2(a.end, b.end) };
    else
-      return { 0, -1 };
+      return { 0, 0 };
 }
 
-
 inline brw_range
 clip_end(brw_range r, int n)
 {
@@ -322,7 +320,7 @@ struct brw_ip_ranges {
 
    brw_range range(const bblock_t *block) const {
       int start = start_ip[block->num];
-      return { start, start + (int)block->num_instructions - 1 };
+      return { start, start + (int)block->num_instructions };
    }
 
 private:

src/intel/compiler/brw_analysis_liveness.cpp

@@ -106,7 +106,7 @@ brw_live_variables::setup_def_use()
 
       assert(ip == bd->ip_range.start);
       if (block->num > 0)
-         assert(block_data[block->num - 1].ip_range.end == ip - 1);
+         assert(block_data[block->num - 1].ip_range.end == ip);
 
       foreach_inst_in_block(brw_inst, inst, block) {
          /* Set use[] for this instruction */
@@ -259,14 +259,8 @@ brw_live_variables::brw_live_variables(const brw_shader *s)
       }
    }
 
-   vars_range = linear_alloc_array(lin_ctx, brw_range, num_vars);
-   for (int i = 0; i < num_vars; i++)
-      vars_range[i] = { MAX_INSTRUCTION, -1 };
-
-   vgrf_range = linear_alloc_array(lin_ctx, brw_range, num_vgrfs);
-   for (int i = 0; i < num_vgrfs; i++)
-      vgrf_range[i] = { MAX_INSTRUCTION, -1 };
-
+   vars_range = linear_zalloc_array(lin_ctx, brw_range, num_vars);
+   vgrf_range = linear_zalloc_array(lin_ctx, brw_range, num_vgrfs);
    block_data = linear_alloc_array(lin_ctx, struct block_data, cfg->num_blocks);
 
    bitset_words = BITSET_WORDS(num_vars);

src/intel/compiler/brw_reg_allocate.cpp

@@ -1086,7 +1086,7 @@ brw_reg_alloc::alloc_spill_reg(unsigned size, int ip)
    assert(n == first_vgrf_node + vgrf);
    assert(n == first_spill_node + spill_node_count);
 
-   brw_range spill_reg_range{ ip - 1, ip + 1 };
+   brw_range spill_reg_range{ ip - 1, ip + 2 };
    setup_live_interference(n, spill_reg_range);
 
    /* Add interference between this spill node and any other spill nodes for