diff options
| author | Matt Turner <[email protected]> | 2015-05-14 22:23:22 -0700 |
|---|---|---|
| committer | Matt Turner <[email protected]> | 2015-05-18 10:11:36 -0700 |
| commit | 81deefc45ba7b7d3b2b5e7ccf9e1680df6e31e3a (patch) | |
| tree | 7c09baa4660f8379d6084a03d7cac6c2accaff3b /src | |
| parent | 1e4e17fbd9296cc5064aabdb351a894d10190cb6 (diff) | |
i965/fs: Unrestrict constant propagation into integer multiply.
Gen8+'s MUL instruction doesn't ignore the high 16-bits of one source
like on earlier platforms, so we can constant propagate into it without
worry. Integer multiplies (not into the accumulator, which is done for
imul_high) are lowered in lower_integer_multiplication(), so it's safe
there as well.
On Broadwell, fragment shaders only:
total instructions in shared programs: 4377769 -> 4377451 (-0.01%)
instructions in affected programs: 48064 -> 47746 (-0.66%)
helped: 156
On Broadwell, vertex shaders only:
total instructions in shared programs: 2858885 -> 2856313 (-0.09%)
instructions in affected programs: 26380 -> 23808 (-9.75%)
helped: 134
On Broadwell, vertex shaders only (with INTEL_USE_NIR=1):
total instructions in shared programs: 2911688 -> 2865984 (-1.57%)
instructions in affected programs: 1421715 -> 1376011 (-3.21%)
helped: 6186
Reviewed-by: Jason Ekstrand <[email protected]>
Diffstat (limited to 'src')
| -rw-r--r-- | src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp index 52bfa921dc3..c92aae4b1d6 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp @@ -541,8 +541,16 @@ fs_visitor::try_constant_propagate(fs_inst *inst, acp_entry *entry) /* Fit this constant in by commuting the operands. * Exception: we can't do this for 32-bit integer MUL/MACH * because it's asymmetric. + * + * The BSpec says for Broadwell that + * + * "When multiplying DW x DW, the dst cannot be accumulator." + * + * Integer MUL with a non-accumulator destination will be lowered + * by lower_integer_multiplication(), so don't restrict it. */ - if ((inst->opcode == BRW_OPCODE_MUL || + if (((inst->opcode == BRW_OPCODE_MUL && + inst->dst.is_accumulator()) || inst->opcode == BRW_OPCODE_MACH) && (inst->src[1].type == BRW_REGISTER_TYPE_D || inst->src[1].type == BRW_REGISTER_TYPE_UD)) |