[Mesa-dev] [PATCH] glsl: Use a separate div_to_mul_rcp lowering flag for integers.
eric at anholt.net
Sun Aug 28 17:38:22 PDT 2011
On Sat, 27 Aug 2011 20:18:55 -0700, Kenneth Graunke <kenneth at whitecape.org> wrote:
> From: Bryan Cain <bryancain3 at 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 <bryancain3 at gmail.com>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> case ir_binop_div:
> - if (lowering(DIV_TO_MUL_RCP))
> + if (lowering(INT_DIV_TO_MUL_RCP) && ir->operands->type->is_integer())
> + int_div_to_mul_rcp(ir);
> + else if (lowering(DIV_TO_MUL_RCP))
Sure looks odd to me for one of these to be checking the type and ther
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