It also doesn't hold true for inf and nan inputs with ieee754 math (just like 0 should be all nan, and in particular making a 1.0 out of a nan that way sounds sort of broken). Earlier glsl versions though had pretty much undefined behavior for infs/nans. Newer versions have more clearly defined behavior, but still say "NaNs or not required to be generated" and "operations and built-in functions that operate on a NaN are not required to return a NaN as the result". Thus my guess is that this is ok.
Roland Am 07.08.2014 23:13, schrieb Patrick Baggett: > Would this be conformant to GLSL spec if X had a runtime value of 0? > Seems unsafe to replace X / X with 1 without a runtime test...maybe GLSL > spec allows such optimizations. > > > On Thu, Aug 7, 2014 at 3:51 PM, <thomashellan...@gmail.com > <mailto:thomashellan...@gmail.com>> wrote: > > From: Thomas Helland <thomashellan...@gmail.com > <mailto:thomashellan...@gmail.com>> > > Shows no changes for shader-db. > > Signed-off-by: Thomas Helland <thomashelland90 at gmail.com > > <https://urldefense.proofpoint.com/v1/url?u=http://gmail.com&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=F4msKE2WxRzA%2BwN%2B25muztFm5TSPwE8HKJfWfR2NgfY%3D%0A&m=024s8S3qVXdOk1UaX8WU6nPiFZ1b0BcBbWJOFGPgJFM%3D%0A&s=57d5e398c7b48e96a78b2903fd2a9b3310fb2ff07b32213a434528a43bfbb1e2>> > --- > src/glsl/opt_algebraic.cpp | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp > index 21bf332..a49752d 100644 > --- a/src/glsl/opt_algebraic.cpp > +++ b/src/glsl/opt_algebraic.cpp > @@ -513,6 +513,8 @@ > ir_algebraic_visitor::handle_expression(ir_expression *ir) > } > if (is_vec_one(op_const[1])) > return ir->operands[0]; > + if(ir->operands[0]->equals(ir->operands[1])) > + return new(mem_ctx) ir_constant(1.0f, 1); > break; > > case ir_binop_dot: > -- > 2.0.3 > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org <mailto:mesa-dev@lists.freedesktop.org> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > > <https://urldefense.proofpoint.com/v1/url?u=http://lists.freedesktop.org/mailman/listinfo/mesa-dev&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=F4msKE2WxRzA%2BwN%2B25muztFm5TSPwE8HKJfWfR2NgfY%3D%0A&m=024s8S3qVXdOk1UaX8WU6nPiFZ1b0BcBbWJOFGPgJFM%3D%0A&s=075157b65ef32d58d0596ad07524450cd8f32351f15292269ee125be3031acde> > > > > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > https://urldefense.proofpoint.com/v1/url?u=http://lists.freedesktop.org/mailman/listinfo/mesa-dev&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=F4msKE2WxRzA%2BwN%2B25muztFm5TSPwE8HKJfWfR2NgfY%3D%0A&m=024s8S3qVXdOk1UaX8WU6nPiFZ1b0BcBbWJOFGPgJFM%3D%0A&s=075157b65ef32d58d0596ad07524450cd8f32351f15292269ee125be3031acde > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
