Mesa (7.10): i965: Refactor Sandybridge implied move handling.

[Ian Romanick]

Module: Mesa
Branch: 7.10
Commit: 773ea1a2345b5d5f8291339a02d7cacb5ea7302e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=773ea1a2345b5d5f8291339a02d7cacb5ea7302e

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Wed Mar 16 14:09:17 2011 -0700

i965: Refactor Sandybridge implied move handling.

This is actually a squash of the following two commits.  The first
caused a regression, and the second fixes it.  The refactor of the
first is needed for another patch that fixes an SNB bug.

    i965: Refactor Sandybridge implied move handling.

    This was open-coded in three different places, and more are necessary.
    Extract this into a function so it can be reused.

    Unfortunately, not all variations were the same: in particular, one set
    compression control and checked that the source register was not
    ARF_NULL.  This seemed like a good idea, so all cases now do so.
    (cherry picked from commit 9a21bc640188e4078075b9f8e6701853a4f0bbe4)

    i965: Fix null register use in Sandybridge implied move resolution.

    Fixes regressions caused by commit 9a21bc6401, namely GPU hangs when
    running gnome-shell or compiz (Mesa bugs #35820 and #35853).

    I incorrectly refactored the case that dealt with ARF_NULL; even in that
    case, the source register needs to be changed to the MRF.

    NOTE: This is a candidate for the 7.10 branch (if 9a21bc6401 is
    cherry-picked, take this one too).
    (cherry picked from commit a019dd0d6e5bba00e8ee7818e004ee42ca507102)

---

 src/mesa/drivers/dri/i965/brw_eu_emit.c |   67 ++++++++++++++----------------
 1 files changed, 31 insertions(+), 36 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c b/src/mesa/drivers/dri/i965/brw_eu_emit.c
index 88131c4..33b6412 100644
--- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
@@ -52,6 +52,34 @@ static void guess_execution_size(struct brw_compile *p,
 }
 
 
+/**
+ * Prior to Sandybridge, the SEND instruction accepted non-MRF source
+ * registers, implicitly moving the operand to a message register.
+ *
+ * On Sandybridge, this is no longer the case.  This function performs the
+ * explicit move; it should be called before emitting a SEND instruction.
+ */
+static void
+gen6_resolve_implied_move(struct brw_compile *p,
+			  struct brw_reg *src,
+			  GLuint msg_reg_nr)
+{
+   struct intel_context *intel = &p->brw->intel;
+   if (intel->gen != 6)
+      return;
+
+   if (src->file != BRW_ARCHITECTURE_REGISTER_FILE || src->nr != BRW_ARF_NULL) {
+      brw_push_insn_state(p);
+      brw_set_mask_control(p, BRW_MASK_DISABLE);
+      brw_set_compression_control(p, BRW_COMPRESSION_NONE);
+      brw_MOV(p, retype(brw_message_reg(msg_reg_nr), BRW_REGISTER_TYPE_UD),
+	      retype(*src, BRW_REGISTER_TYPE_UD));
+      brw_pop_insn_state(p);
+   }
+   *src = brw_message_reg(msg_reg_nr);
+}
+
+
 static void brw_set_dest(struct brw_compile *p,
 			 struct brw_instruction *insn,
 			 struct brw_reg dest)
@@ -1966,20 +1994,7 @@ void brw_SAMPLE(struct brw_compile *p,
    {
       struct brw_instruction *insn;
    
-      /* Sandybridge doesn't have the implied move for SENDs,
-       * and the first message register index comes from src0.
-       */
-      if (intel->gen >= 6) {
-	 if (src0.file != BRW_ARCHITECTURE_REGISTER_FILE ||
-	     src0.nr != BRW_ARF_NULL) {
-	    brw_push_insn_state(p);
-	    brw_set_mask_control( p, BRW_MASK_DISABLE );
-	    brw_set_compression_control(p, BRW_COMPRESSION_NONE);
-	    brw_MOV(p, retype(brw_message_reg(msg_reg_nr), src0.type), src0);
-	    brw_pop_insn_state(p);
-	 }
-	 src0 = brw_message_reg(msg_reg_nr);
-      }
+      gen6_resolve_implied_move(p, &src0, msg_reg_nr);
 
       insn = next_insn(p, BRW_OPCODE_SEND);
       insn->header.predicate_control = 0; /* XXX */
@@ -2034,17 +2049,7 @@ void brw_urb_WRITE(struct brw_compile *p,
    struct intel_context *intel = &p->brw->intel;
    struct brw_instruction *insn;
 
-   /* Sandybridge doesn't have the implied move for SENDs,
-    * and the first message register index comes from src0.
-    */
-   if (intel->gen >= 6) {
-      brw_push_insn_state(p);
-      brw_set_mask_control( p, BRW_MASK_DISABLE );
-      brw_MOV(p, retype(brw_message_reg(msg_reg_nr), BRW_REGISTER_TYPE_UD),
-	      retype(src0, BRW_REGISTER_TYPE_UD));
-      brw_pop_insn_state(p);
-      src0 = brw_message_reg(msg_reg_nr);
-   }
+   gen6_resolve_implied_move(p, &src0, msg_reg_nr);
 
    insn = next_insn(p, BRW_OPCODE_SEND);
 
@@ -2154,17 +2159,7 @@ void brw_ff_sync(struct brw_compile *p,
    struct intel_context *intel = &p->brw->intel;
    struct brw_instruction *insn;
 
-   /* Sandybridge doesn't have the implied move for SENDs,
-    * and the first message register index comes from src0.
-    */
-   if (intel->gen >= 6) {
-      brw_push_insn_state(p);
-      brw_set_mask_control( p, BRW_MASK_DISABLE );
-      brw_MOV(p, retype(brw_message_reg(msg_reg_nr), BRW_REGISTER_TYPE_UD),
-	      retype(src0, BRW_REGISTER_TYPE_UD));
-      brw_pop_insn_state(p);
-      src0 = brw_message_reg(msg_reg_nr);
-   }
+   gen6_resolve_implied_move(p, &src0, msg_reg_nr);
 
    insn = next_insn(p, BRW_OPCODE_SEND);
    brw_set_dest(p, insn, dest);