i965/urb: fixes division by zero

[mesa.git] / src / mesa / drivers / dri / i965 / brw_fs_cmod_propagation.cpp

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 58890ee9bede5086332ed9d8df526fbc513417bc..b5badaef9774e375c76eb1cdf09ca50a20568d15 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp
@@ -22,8 +22,8 @@
  */
 
 #include "brw_fs.h"
-#include "brw_fs_live_variables.h"
 #include "brw_cfg.h"
+#include "brw_eu.h"
 
 /** @file brw_fs_cmod_propagation.cpp
  *
@@ -49,7 +49,7 @@
  */
 
 static bool
-opt_cmod_propagation_local(fs_visitor *v, bblock_t *block)
+opt_cmod_propagation_local(bblock_t *block)
 {
    bool progress = false;
    int ip = block->end_ip + 1;
@@ -57,14 +57,28 @@ opt_cmod_propagation_local(fs_visitor *v, bblock_t *block)
    foreach_inst_in_block_reverse_safe(fs_inst, inst, block) {
       ip--;
 
-      if ((inst->opcode != BRW_OPCODE_CMP &&
+      if ((inst->opcode != BRW_OPCODE_AND &&
+           inst->opcode != BRW_OPCODE_CMP &&
            inst->opcode != BRW_OPCODE_MOV) ||
           inst->predicate != BRW_PREDICATE_NONE ||
           !inst->dst.is_null() ||
-          inst->src[0].file != GRF ||
+          inst->src[0].file != VGRF ||
           inst->src[0].abs)
          continue;
 
+      /* Only an AND.NZ can be propagated.  Many AND.Z instructions are
+       * generated (for ir_unop_not in fs_visitor::emit_bool_to_cond_code).
+       * Propagating those would require inverting the condition on the CMP.
+       * This changes both the flag value and the register destination of the
+       * CMP.  That result may be used elsewhere, so we can't change its value
+       * on a whim.
+       */
+      if (inst->opcode == BRW_OPCODE_AND &&
+          !(inst->src[1].is_one() &&
+            inst->conditional_mod == BRW_CONDITIONAL_NZ &&
+            !inst->src[0].negate))
+         continue;
+
       if (inst->opcode == BRW_OPCODE_CMP && !inst->src[1].is_zero())
          continue;
 
@@ -73,15 +87,33 @@ opt_cmod_propagation_local(fs_visitor *v, bblock_t *block)
          continue;
 
       bool read_flag = false;
-      foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst,
-                                                  block) {
+      foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst) {
          if (scan_inst->overwrites_reg(inst->src[0])) {
             if (scan_inst->is_partial_write() ||
-                scan_inst->dst.reg_offset != inst->src[0].reg_offset)
+                scan_inst->dst.reg_offset != inst->src[0].reg_offset ||
+                scan_inst->exec_size != inst->exec_size)
+               break;
+
+            /* CMP's result is the same regardless of dest type. */
+            if (inst->conditional_mod == BRW_CONDITIONAL_NZ &&
+                scan_inst->opcode == BRW_OPCODE_CMP &&
+                (inst->dst.type == BRW_REGISTER_TYPE_D ||
+                 inst->dst.type == BRW_REGISTER_TYPE_UD)) {
+               inst->remove(block);
+               progress = true;
+               break;
+            }
+
+            /* If the AND wasn't handled by the previous case, it isn't safe
+             * to remove it.
+             */
+            if (inst->opcode == BRW_OPCODE_AND)
                break;
 
             /* Comparisons operate differently for ints and floats */
-            if (scan_inst->dst.type != inst->dst.type)
+            if (scan_inst->dst.type != inst->dst.type &&
+                (scan_inst->dst.type == BRW_REGISTER_TYPE_F ||
+                 inst->dst.type == BRW_REGISTER_TYPE_F))
                break;
 
             /* If the instruction generating inst's source also wrote the
@@ -128,7 +160,7 @@ fs_visitor::opt_cmod_propagation()
    bool progress = false;
 
    foreach_block_reverse(block, cfg) {
-      progress = opt_cmod_propagation_local(this, block) || progress;
+      progress = opt_cmod_propagation_local(block) || progress;
    }
 
    if (progress)