Mesa (master): i965/fs: Perform CSE on load_payload instructions if it' s not a copy.
Matt Turner
mattst88 at kemper.freedesktop.org
Tue Jun 17 17:07:19 UTC 2014
Module: Mesa
Branch: master
Commit: 31ae9c25ff07681f59e6ffc53c039e842cb39464
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=31ae9c25ff07681f59e6ffc53c039e842cb39464
Author: Matt Turner <mattst88 at gmail.com>
Date: Sun Mar 30 12:41:55 2014 -0700
i965/fs: Perform CSE on load_payload instructions if it's not a copy.
Since CSE creates instructions, if we let CSE generate things register
coalescing can't remove, bad things will happen. Only let CSE combine
non-copy load_payloads.
E.g., allow CSE to handle this
load_payload vgrf4+0, vgrf5, vgrf6
but not this
load_payload vgrf4+0, vgrf5+0, vgrf5+1
---
src/mesa/drivers/dri/i965/brw_fs_cse.cpp | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
index abaf688..a319307 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
@@ -43,6 +43,22 @@ struct aeb_entry : public exec_node {
}
static bool
+is_copy_payload(const fs_inst *inst)
+{
+ const int reg = inst->src[0].reg;
+ if (inst->src[0].reg_offset != 0)
+ return false;
+
+ for (int i = 1; i < inst->sources; i++) {
+ if (inst->src[i].reg != reg ||
+ inst->src[i].reg_offset != i) {
+ return false;
+ }
+ }
+ return true;
+}
+
+static bool
is_expression(const fs_inst *const inst)
{
switch (inst->opcode) {
@@ -84,6 +100,8 @@ is_expression(const fs_inst *const inst)
case SHADER_OPCODE_SIN:
case SHADER_OPCODE_COS:
return inst->mlen == 0;
+ case SHADER_OPCODE_LOAD_PAYLOAD:
+ return !is_copy_payload(inst);
default:
return false;
}
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