[Mesa-dev] [PATCH 24/57] i965/fs: Drop fs_inst::overwrites_reg() in favor of regions_overlap().

[Francisco Jerez]

fs_inst::overwrites_reg is rather easy to misuse because it cannot
tell how large the register region starting at 'reg' is, so in cases
where the destination region starts after 'reg' it may give a
misleading result.  regions_overlap() is somewhat more verbose to use
but handles arbitrary overlap correctly so it should generally be used
instead.
---
 src/mesa/drivers/dri/i965/brw_fs.cpp                      | 6 ------
 src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp     | 3 ++-
 src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp     | 6 ++++--
 src/mesa/drivers/dri/i965/brw_fs_cse.cpp                  | 4 +++-
 src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp    | 6 ++++--
 src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp | 3 ++-
 src/mesa/drivers/dri/i965/brw_ir_fs.h                     | 1 -
 7 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 57a3494..98da06c 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -241,12 +241,6 @@ fs_inst::equals(fs_inst *inst) const
 }
 
 bool
-fs_inst::overwrites_reg(const fs_reg &reg) const
-{
-   return reg.in_range(dst, DIV_ROUND_UP(size_written, REG_SIZE));
-}
-
-bool
 fs_inst::is_send_from_grf() const
 {
    switch (opcode) {
diff --git a/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp
index 291ae4c..2d50c92 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp
@@ -88,7 +88,8 @@ opt_cmod_propagation_local(const gen_device_info *devinfo, bblock_t *block)
 
       bool read_flag = false;
       foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst) {
-         if (scan_inst->overwrites_reg(inst->src[0])) {
+         if (regions_overlap(scan_inst->dst, scan_inst->size_written,
+                             inst->src[0], inst->size_read(0))) {
             if (scan_inst->is_partial_write() ||
                 scan_inst->dst.offset != inst->src[0].offset ||
                 scan_inst->exec_size != inst->exec_size)
diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
index 4a56aff..bd534bf 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -161,8 +161,10 @@ fs_copy_prop_dataflow::setup_initial_values()
 
          /* Mark ACP entries which are killed by this instruction. */
          for (int i = 0; i < num_acp; i++) {
-            if (inst->overwrites_reg(acp[i]->dst) ||
-                inst->overwrites_reg(acp[i]->src)) {
+            if (regions_overlap(inst->dst, inst->size_written,
+                                acp[i]->dst, acp[i]->size_written) ||
+                regions_overlap(inst->dst, inst->size_written,
+                                acp[i]->src, acp[i]->size_read)) {
                BITSET_SET(bd[block->num].kill, i);
             }
          }
diff --git a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
index 2acbfea..48220ef 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
@@ -335,7 +335,9 @@ fs_visitor::opt_cse_local(bblock_t *block)
             /* Kill all AEB entries that use the destination we just
              * overwrote.
              */
-            if (inst->overwrites_reg(entry->generator->src[i])) {
+            if (regions_overlap(inst->dst, inst->size_written,
+                                entry->generator->src[i],
+                                entry->generator->size_read(i))) {
                entry->remove();
                ralloc_free(entry);
                break;
diff --git a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
index 694cc0b..f56f05b 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
@@ -138,8 +138,10 @@ can_coalesce_vars(brw::fs_live_variables *live_intervals,
          if (scan_ip > end_ip)
             return true; /* registers do not interfere */
 
-         if (scan_inst->overwrites_reg(inst->dst) ||
-             scan_inst->overwrites_reg(inst->src[0]))
+         if (regions_overlap(scan_inst->dst, scan_inst->size_written,
+                             inst->dst, inst->size_written) ||
+             regions_overlap(scan_inst->dst, scan_inst->size_written,
+                             inst->src[0], inst->size_read(0)))
             return false; /* registers interfere */
       }
    }
diff --git a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
index 60bb1c0..1c97a50 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
@@ -64,7 +64,8 @@ opt_saturate_propagation_local(fs_visitor *v, bblock_t *block)
 
       bool interfered = false;
       foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst) {
-         if (scan_inst->overwrites_reg(inst->src[0])) {
+         if (regions_overlap(scan_inst->dst, scan_inst->size_written,
+                             inst->src[0], inst->size_read(0))) {
             if (scan_inst->is_partial_write() ||
                 (scan_inst->dst.type != inst->dst.type &&
                  !scan_inst->can_change_types()))
diff --git a/src/mesa/drivers/dri/i965/brw_ir_fs.h b/src/mesa/drivers/dri/i965/brw_ir_fs.h
index c688345..5275953 100644
--- a/src/mesa/drivers/dri/i965/brw_ir_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_ir_fs.h
@@ -334,7 +334,6 @@ public:
    void resize_sources(uint8_t num_sources);
 
    bool equals(fs_inst *inst) const;
-   bool overwrites_reg(const fs_reg &reg) const;
    bool is_send_from_grf() const;
    bool is_partial_write() const;
    bool is_copy_payload(const brw::simple_allocator &grf_alloc) const;
-- 
2.9.0