Attachment 55689 Details for Bug 44333 – Possible fix for the optimization

[patch] Possible fix for the optimization

0001-i965-fs-Don-t-allow-vectors-in-try_rewrite_rhs_to_ds.patch (text/plain), 1.57 KB, created by Kenneth Graunke on 2012-01-17 09:57:01 UTC

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Creator: Kenneth Graunke

Created: 2012-01-17 09:57:01 UTC

Size: 1.57 KB

patch

obsolete

>From 1ddfbe99ac2275f4036ae8f044e1d47d2db4f894 Mon Sep 17 00:00:00 2001
>From: Kenneth Graunke <kenneth@whitecape.org>
>Date: Sat, 14 Jan 2012 01:44:15 -0800
>Subject: [PATCH] i965/fs: Don't allow vectors in try_rewrite_rhs_to_dst.
>
>In SOA mode, vectors are stored in up to four separate registers, and
>cannot be moved by a single instruction---it takes one per component.
>
>Unfortunately, the try_rewrite_rhs_to_dst optimization breaks for
>assignments of whole vectors: it rewrites the last instruction that
>generated part of the RHS to point at the MOV's dst.x and blithely
>reports that no further work is necessary.  The y, z, and w components
>never get copied.
>
>Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
>---
> src/mesa/drivers/dri/i965/brw_fs_visitor.cpp |    5 +----
> 1 files changed, 1 insertions(+), 4 deletions(-)
>
>diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
>index 44c9ee8..e096d7c 100644
>--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
>+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
>@@ -551,10 +551,7 @@ fs_visitor::try_rewrite_rhs_to_dst(ir_assignment *ir,
>       return false; /* No instructions generated to work with. */
> 
>    /* Only attempt if we're doing a direct assignment. */
>-   if (ir->condition ||
>-       !(ir->lhs->type->is_scalar() ||
>-        (ir->lhs->type->is_vector() &&
>-         ir->write_mask == (1 << ir->lhs->type->vector_elements) - 1)))
>+   if (ir->condition || !ir->lhs->type->is_scalar())
>       return false;
> 
>    /* Make sure the last instruction generated our source reg. */
>-- 
>1.7.7.5
>

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Attachments on bug 44333: 54988 | 55089 | 55689

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