qemu /
qemu /
d54c56156f409344f8cf232f1e7ee68defa811b9 Hexagon (target/hexagon) Short-circuit packet register writes
In certain cases, we can avoid the overhead of writing to hex_new_value
and write directly to hex_gpr. We add need_commit field to DisasContext
indicating if the end-of-packet commit is needed. If it is not needed,
get_result_gpr() and get_result_gpr_pair() can return hex_gpr.
We pass the ctx->need_commit to helpers when needed.
Finally, we can early-exit from gen_reg_writes during packet commit.
There are a few instructions whose semantics write to the result before
reading all the inputs. Therefore, the idef-parser generated code is
incompatible with short-circuit. We tell idef-parser to skip them.
For debugging purposes, we add a cpu property to turn off short-circuit.
When the short-circuit property is false, we skip the analysis and force
the end-of-packet commit.
Here's a simple example of the TCG generated for
0x004000b4: 0x7800c020 { R0 = #0x1 }
BEFORE:
---- 004000b4
movi_i32 new_r0,$0x1
mov_i32 r0,new_r0
AFTER:
---- 004000b4
movi_i32 r0,$0x1
This patch reintroduces a use of check_for_attrib, so we remove the
G_GNUC_UNUSED added earlier in this series.
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Brian Cain <bcain@quicinc.com>
Message-Id: <20230427230012.3800327-12-tsimpson@quicinc.com>
16 files changed
