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-rw-r--r--src/mesa/drivers/dri/i965/brw_fs_generator.cpp18
1 files changed, 18 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 8654ca4d0af..ff8d37e2c0c 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -1726,6 +1726,24 @@ fs_generator::generate_code(const cfg_t *cfg, int dispatch_width)
unsigned int last_insn_offset = p->next_insn_offset;
bool multiple_instructions_emitted = false;
+ /* From the Broadwell PRM, Volume 7, "3D-Media-GPGPU", in the
+ * "Register Region Restrictions" section: for BDW, SKL:
+ *
+ * "A POW/FDIV operation must not be followed by an instruction
+ * that requires two destination registers."
+ *
+ * The documentation is often lacking annotations for Atom parts,
+ * and empirically this affects CHV as well.
+ */
+ if (devinfo->gen >= 8 &&
+ p->nr_insn > 1 &&
+ brw_inst_opcode(devinfo, brw_last_inst) == BRW_OPCODE_MATH &&
+ brw_inst_math_function(devinfo, brw_last_inst) == BRW_MATH_FUNCTION_POW &&
+ inst->dst.component_size(inst->exec_size) > REG_SIZE) {
+ brw_NOP(p);
+ last_insn_offset = p->next_insn_offset;
+ }
+
if (unlikely(debug_flag))
annotate(p->devinfo, &annotation, cfg, inst, p->next_insn_offset);