Attachment 96764 Details for Bug 76749 – fix vs copy propagation

[patch] fix vs copy propagation

0001-i965-vec4-fix-record-clearing-in-copy-propagation.patch (text/plain), 2.19 KB, created by Chia-I Wu on 2014-04-02 07:59:45 UTC

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Creator: Chia-I Wu

Created: 2014-04-02 07:59:45 UTC

Size: 2.19 KB

patch

obsolete

>From 478ad9b1791be37ac10d62cca5925bc2152d45e2 Mon Sep 17 00:00:00 2001
>From: Chia-I Wu <olv@lunarg.com>
>Date: Wed, 2 Apr 2014 15:12:49 +0800
>Subject: [PATCH] i965/vec4: fix record clearing in copy propagation
>
>Given
>
>  mov vgrf7.0:F, vgrf9.xyxz:F
>  add vgrf9.0.xyz:F, vgrf4.xyzw:F, vgrf5.xyzw:F
>  add vgrf10.0.x:F, vgrf6.xyzw:F, vgrf7.wwww:F
>
>the last instruction would be wrongly changed to
>
>  add vgrf10.0.x:F, vgrf6.xyzw:F, vgrf9.zzzz:F
>
>during copy propagation.
>
>The issue is that when deciding if a record should be cleared, the old code
>checked for
>
>  inst->dst.writemask & (1 << ch)
>
>instead of
>
>  inst->dst.writemask & (1 << BRW_GET_SWZ(src->swizzle, ch))
>---
> .../drivers/dri/i965/brw_vec4_copy_propagation.cpp  | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
>diff --git a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
>index c8feff8..1711005 100644
>--- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
>+++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
>@@ -58,6 +58,21 @@ is_dominated_by_previous_instruction(vec4_instruction *inst)
> }
> 
> static bool
>+is_channel_updated(vec4_instruction *inst, src_reg *values[4], int ch)
>+{
>+   const src_reg *src = values[ch];
>+
>+   /* consider GRF only */
>+   assert(inst->dst.file == GRF);
>+   if (!src || src->file != GRF)
>+      return false;
>+
>+   return (src->reg == inst->dst.reg &&
>+	   src->reg_offset == inst->dst.reg_offset &&
>+	   inst->dst.writemask & (1 << BRW_GET_SWZ(src->swizzle, ch)));
>+}
>+
>+static bool
> try_constant_propagation(vec4_instruction *inst, int arg, src_reg *values[4])
> {
>    /* For constant propagation, we only handle the same constant
>@@ -353,11 +368,7 @@ vec4_visitor::opt_copy_propagation()
> 	 else {
> 	    for (int i = 0; i < virtual_grf_reg_count; i++) {
> 	       for (int j = 0; j < 4; j++) {
>-		  if (inst->dst.writemask & (1 << j) &&
>-		      cur_value[i][j] &&
>-		      cur_value[i][j]->file == GRF &&
>-		      cur_value[i][j]->reg == inst->dst.reg &&
>-		      cur_value[i][j]->reg_offset == inst->dst.reg_offset) {
>+		  if (is_channel_updated(inst, cur_value[i], j)){
> 		     cur_value[i][j] = NULL;
> 		  }
> 	       }
>-- 
>1.8.3.1
>

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