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authorBen Widawsky <benjamin.widawsky@intel.com>2014-11-21 10:47:41 -0800
committerBen Widawsky <benjamin.widawsky@intel.com>2014-11-21 12:08:46 -0800
commit88fea85f09e2252035bec66ab26c375b45b000f5 (patch)
tree102448da1017b34426207e17c555a9230aae4a9d
parent156f565f9eb36dad3cd959952724bc54f9ff21ea (diff)
i965/vec4/gen8: Handle the MUL dest hazard exception
Fix one of the few cases where we can't reliable touch the destination hazard bits. I am explicitly doing this patch individually so it is easy to backport. I was tempted to do this patch before the previous patch which reorganized the code, but I believe even doing that first, this is still easy to backport. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84212 Signed-off-by: Ben Widawsky <ben@bwidawsk.net> Reviewed-by: Matt Turner <mattst88@gmail.com>
-rw-r--r--src/mesa/drivers/dri/i965/brw_vec4.cpp20
-rw-r--r--src/mesa/drivers/dri/i965/brw_vec4.h1
2 files changed, 19 insertions, 2 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index 655299472ff..f1d59bda846 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -841,9 +841,25 @@ vec4_visitor::move_push_constants_to_pull_constants()
}
/* Conditions for which we want to avoid setting the dependency control bits */
-static bool
-is_dep_ctrl_unsafe(const vec4_instruction *inst)
+bool
+vec4_visitor::is_dep_ctrl_unsafe(const vec4_instruction *inst)
{
+#define IS_DWORD(reg) \
+ (reg.type == BRW_REGISTER_TYPE_UD || \
+ reg.type == BRW_REGISTER_TYPE_D)
+
+ /* From the destination hazard section of the spec:
+ * > Instructions other than send, may use this control as long as operations
+ * > that have different pipeline latencies are not mixed.
+ */
+ if (brw->gen >= 8) {
+ if (inst->opcode == BRW_OPCODE_MUL &&
+ IS_DWORD(inst->src[0]) &&
+ IS_DWORD(inst->src[1]))
+ return true;
+ }
+#undef IS_DWORD
+
/*
* mlen:
* In the presence of send messages, totally interrupt dependency
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index 44aea0ea8ee..aac5954557c 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -390,6 +390,7 @@ public:
bool opt_cse();
bool opt_algebraic();
bool opt_register_coalesce();
+ bool is_dep_ctrl_unsafe(const vec4_instruction *inst);
void opt_set_dependency_control();
void opt_schedule_instructions();