On Sun, 28 Aug 2011 20:51:10 -0500, Bryan Cain <bryanca...@gmail.com> wrote: > On 08/28/2011 07:38 PM, Eric Anholt wrote: > > On Sat, 27 Aug 2011 20:18:55 -0700, Kenneth Graunke <kenn...@whitecape.org> > > wrote: > >> From: Bryan Cain <bryanca...@gmail.com> > >> > >> Using multiply and reciprocal for integer division involves potentially > >> lossy floating point conversions. This is okay for older GPUs that > >> represent integers as floating point, but undesirable for GPUs with > >> native integer division instructions. > >> > >> TGSI, for example, has UDIV/IDIV instructions for integer division, > >> so it makes sense to handle this directly. Likewise for i965. > >> > >> Signed-off-by: Bryan Cain <bryanca...@gmail.com> > >> Signed-off-by: Kenneth Graunke <kenn...@whitecape.org> > > > >> --- > >> case ir_binop_div: > >> - if (lowering(DIV_TO_MUL_RCP)) > >> + if (lowering(INT_DIV_TO_MUL_RCP) && > >> ir->operands[1]->type->is_integer()) > >> + int_div_to_mul_rcp(ir); > >> + else if (lowering(DIV_TO_MUL_RCP)) > >> div_to_mul_rcp(ir); > >> break; > >> > > Sure looks odd to me for one of these to be checking the type and ther > > other not. > > It works, though. If it's not an integer type, it's going to be a float > type.
Not to my reading. If ir->op[1]->type->is_integer() && !lowering(INT_DIV_TO_MULL_RCP) && lowering(DIV_TO_MUL_RCP), then assert(ir->operands[1]->type->is_float()) should fail.
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