[Mesa-dev] [Mesa-stable] [PATCH 2/3] i965/fs: Use fs_inst::overwrites_reg() in saturate propagation.

[Ian Romanick]

On 02/19/2015 03:29 PM, Matt Turner wrote:
> On Thu, Feb 19, 2015 at 3:25 PM, Ian Romanick <idr at freedesktop.org> wrote:
>> On 02/11/2015 02:54 PM, Matt Turner wrote:
>>> This is safer and matches the conditional_mod propagation pass.
>>>
>>> Cc: <mesa-stable at lists.freedesktop.org>
>>> ---
>>>  .../dri/i965/brw_fs_saturate_propagation.cpp       |  8 ++---
>>>  .../dri/i965/test_fs_saturate_propagation.cpp      | 40 ++++++++++++++++++++++
>>>  2 files changed, 44 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
>>> index a9966a4..bc51661 100644
>>> --- a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
>>> +++ b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
>>> @@ -64,10 +64,10 @@ opt_saturate_propagation_local(fs_visitor *v, bblock_t *block)
>>>
>>>        bool interfered = false;
>>>        foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst, block) {
>>> -         if (scan_inst->dst.file == GRF &&
>>> -             scan_inst->dst.reg == inst->src[0].reg &&
>>> -             scan_inst->dst.reg_offset == inst->src[0].reg_offset &&
>>> -             !scan_inst->is_partial_write()) {
>>> +         if (scan_inst->overwrites_reg(inst->src[0])) {
>>> +            if (scan_inst->is_partial_write())
>>> +               break;
>>> +
>>>              if (scan_inst->saturate) {
>>>                 inst->saturate = false;
>>>                 progress = true;
>>> diff --git a/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp b/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp
>>> index 2000830..f897bdd 100644
>>> --- a/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp
>>> +++ b/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp
>>> @@ -353,3 +353,43 @@ TEST_F(saturate_propagation_test, intervening_saturating_copy)
>>>     EXPECT_EQ(BRW_OPCODE_MOV, instruction(block0, 2)->opcode);
>>>     EXPECT_FALSE(instruction(block0, 2)->saturate);
>>>  }
>>> +
>>> +TEST_F(saturate_propagation_test, intervening_dest_write)
>>
>> Does this test pass without the other change?
> 
> No. The test is for the bug this is fixing.

Okay... then that also answers my follow-up question about the apparent
behavior change in the other hunk. :)  This patch is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

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