i965/fs.h: Refactor tests for instructions modifying a register.

There's one instance of a potential behavior change: propagate_constants may
now propagate into a part of a vgrf after a different part of it was
overwritten by a send that returns multiple registers.  I don't think we ever
generate IR that meets that condition, but it's something to note if we bisect
behavior change to this.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index de049d5..630150d 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -168,6 +168,15 @@ fs_inst::regs_written()
 }
 
 bool
+fs_inst::overwrites_reg(const fs_reg &reg)
+{
+   return (reg.file == dst.file &&
+           reg.reg == dst.reg &&
+           reg.reg_offset >= dst.reg_offset  &&
+           reg.reg_offset < dst.reg_offset + regs_written());
+}
+
+bool
 fs_inst::is_tex()
 {
    return (opcode == SHADER_OPCODE_TEX ||
@@ -1400,9 +1409,7 @@ fs_visitor::propagate_constants()
         }
 
         if (scan_inst->dst.file == GRF &&
-            scan_inst->dst.reg == inst->dst.reg &&
-            (scan_inst->dst.reg_offset == inst->dst.reg_offset ||
-             scan_inst->regs_written() > 1)) {
+             scan_inst->overwrites_reg(inst->dst)) {
            break;
         }
       }
@@ -1602,16 +1609,8 @@ fs_visitor::register_coalesce()
           !scan_inst->is_tail_sentinel();
           scan_inst = (fs_inst *)scan_inst->next) {
         if (scan_inst->dst.file == GRF) {
-           if (scan_inst->dst.reg == inst->dst.reg &&
-               (scan_inst->dst.reg_offset == inst->dst.reg_offset ||
-                scan_inst->regs_written() > 1)) {
-              interfered = true;
-              break;
-           }
-           if (inst->src[0].file == GRF &&
-               scan_inst->dst.reg == inst->src[0].reg &&
-               (scan_inst->dst.reg_offset == inst->src[0].reg_offset ||
-                scan_inst->regs_written() > 1)) {
+           if (scan_inst->overwrites_reg(inst->dst) ||
+                scan_inst->overwrites_reg(inst->src[0])) {
               interfered = true;
               break;
            }

diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index deb58d8..6e3c46a 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -150,6 +150,7 @@ public:
 
    bool equals(fs_inst *inst);
    int regs_written();
+   bool overwrites_reg(const fs_reg &reg);
    bool is_tex();
    bool is_math();
 

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 106964d..1870f43 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -98,23 +98,11 @@ fs_visitor::opt_copy_propagate_local(void *mem_ctx,
 
       /* kill the destination from the ACP */
       if (inst->dst.file == GRF) {
-        int start_offset = inst->dst.reg_offset;
-        int end_offset = start_offset + inst->regs_written();
-
         foreach_list_safe(entry_node, acp) {
            acp_entry *entry = (acp_entry *)entry_node;
 
-           if (entry->dst.file == GRF &&
-               entry->dst.reg == inst->dst.reg &&
-               entry->dst.reg_offset >= start_offset &&
-               entry->dst.reg_offset < end_offset) {
-              entry->remove();
-              continue;
-           }
-           if (entry->src.file == GRF &&
-               entry->src.reg == inst->dst.reg &&
-               entry->src.reg_offset >= start_offset &&
-               entry->src.reg_offset < end_offset) {
+           if (inst->overwrites_reg(entry->dst) ||
+                inst->overwrites_reg(entry->src)) {
               entry->remove();
            }
         }

diff --git a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
index fd28e14..7bf6698 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
@@ -150,17 +150,11 @@ fs_visitor::opt_cse_local(fs_bblock *block, exec_list *aeb)
       }
 
       /* Kill all AEB entries that use the destination. */
-      int start_offset = inst->dst.reg_offset;
-      int end_offset = start_offset + inst->regs_written();
-
       foreach_list_safe(entry_node, aeb) {
         aeb_entry *entry = (aeb_entry *)entry_node;
 
         for (int i = 0; i < 3; i++) {
-           if (entry->generator->src[i].file == inst->dst.file &&
-               entry->generator->src[i].reg == inst->dst.reg &&
-               entry->generator->src[i].reg_offset >= start_offset &&
-               entry->generator->src[i].reg_offset < end_offset) {
+            if (inst->overwrites_reg(entry->generator->src[i])) {
               entry->remove();
               ralloc_free(entry);
               break;