This will be used for compute-to-mrf, which needs to know when MRFs
get overwritten.
---
src/mesa/drivers/dri/i965/brw_vec4.cpp | 37 ++++++++++++++++++++++++++++++++
src/mesa/drivers/dri/i965/brw_vec4.h | 2 +
2 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp
b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index 5fd4756..2a8d63a 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -43,6 +43,43 @@ vec4_instruction::is_math()
opcode == SHADER_OPCODE_COS ||
opcode == SHADER_OPCODE_POW);
}
+/**
+ * Returns how many MRFs an opcode will write over.
+ *
+ * Note that this is not the 0 or 1 implied writes in an actual gen
+ * instruction -- the generate_* functions generate additional MOVs
+ * for setup.
+ */
+int
+vec4_visitor::implied_mrf_writes(vec4_instruction *inst)
+{
+ if (inst->mlen == 0)
+ return 0;
+
+ switch (inst->opcode) {
+ case SHADER_OPCODE_RCP:
+ case SHADER_OPCODE_RSQ:
+ case SHADER_OPCODE_SQRT:
+ case SHADER_OPCODE_EXP2:
+ case SHADER_OPCODE_LOG2:
+ case SHADER_OPCODE_SIN:
+ case SHADER_OPCODE_COS:
+ return 1;
+ case SHADER_OPCODE_POW:
+ return 2;
+ case VS_OPCODE_URB_WRITE:
+ return 1;
+ case VS_OPCODE_PULL_CONSTANT_LOAD:
+ return 2;
+ case VS_OPCODE_SCRATCH_READ:
+ return 2;
+ case VS_OPCODE_SCRATCH_WRITE:
+ return 3;
+ default:
+ assert(!"not reached");
+ return inst->mlen;
+ }
+}
bool
src_reg::equals(src_reg *r)
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h
b/src/mesa/drivers/dri/i965/brw_vec4.h
index 0f85cdb..e305e6f 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -439,6 +439,8 @@ public:
vec4_instruction *SCRATCH_READ(dst_reg dst, src_reg index);
vec4_instruction *SCRATCH_WRITE(dst_reg dst, src_reg src, src_reg index);
+ int implied_mrf_writes(vec4_instruction *inst);
+
bool try_rewrite_rhs_to_dst(ir_assignment *ir,
dst_reg dst,
src_reg src,
--
1.7.5.4
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