<div dir="ltr"><div>Reviewed-by: Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> </div> <div class="gmail_quote"><div dir="ltr">On Wed, Jan 16, 2019 at 1:32 AM Francisco Jerez <<a href="mailto:currojerez@riseup.net">currojerez@riseup.net</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">The docs are fairly incomplete and inconsistent about it, but this seems to be the reason why half-float destinations are required to be DWORD-aligned on BDW+ projects. This way the regioning lowering pass will make sure that the destination components of W to HF and HF to W conversions are aligned like the corresponding conversion operation with 32-bit execution data type. --- src/intel/compiler/brw_ir_fs.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/src/intel/compiler/brw_ir_fs.h b/src/intel/compiler/brw_ir_fs.h index 3c23fb375e4..08e3d83d910 100644 --- a/src/intel/compiler/brw_ir_fs.h +++ b/src/intel/compiler/brw_ir_fs.h @@ -477,6 +477,27 @@ get_exec_type(const fs_inst *inst) assert(exec_type != BRW_REGISTER_TYPE_B); + /* Promotion of the execution type to 32-bit for conversions from or to + * half-float seems to be consistent with the following text from the + * Cherryview PRM Vol. 7, "Execution Data Type": + * + * "When single precision and half precision floats are mixed between + * source operands or between source and destination operand [..] single + * precision float is the execution datatype." + * + * and from "Register Region Restrictions": + * + * "Conversion between Integer and HF (Half Float) must be DWord aligned + * and strided by a DWord on the destination." + */ + if (type_sz(exec_type) == 2 && + inst->dst.type != exec_type) { + if (exec_type == BRW_REGISTER_TYPE_HF) + exec_type = BRW_REGISTER_TYPE_F; + else if (inst->dst.type == BRW_REGISTER_TYPE_HF) + exec_type = BRW_REGISTER_TYPE_D; + } + return exec_type; } -- 2.19.2 _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org" target="_blank">mesa-dev@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div></div>