nir: add fceil lowering

lowers ceil(x) as -floor(-x)

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index a292ec7..db935c8 100644 (file)
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2130,6 +2130,9 @@ typedef struct nir_shader_compiler_options {
    /** lowers ffract to fsub+ffloor: */
    bool lower_ffract;
 
+   /** lowers fceil to fneg+ffloor+fneg: */
+   bool lower_fceil;
+
    bool lower_ldexp;
 
    bool lower_pack_half_2x16;

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 0d88025..f2a7be0 100644 (file)
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -125,6 +125,7 @@ optimizations = [
    (('flrp@64', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp64'),
    (('ffloor', a), ('fsub', a, ('ffract', a)), 'options->lower_ffloor'),
    (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'),
+   (('fceil', a), ('fneg', ('ffloor', ('fneg', a))), 'options->lower_fceil'),
    (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp32'),
    (('~fadd@32', ('fmul', a, ('fadd', 1.0, ('fneg',         c ))), ('fmul', b,         c )), ('flrp', a, b, c), '!options->lower_flrp32'),
    (('~fadd@64', ('fmul', a, ('fadd', 1.0, ('fneg',         c ))), ('fmul', b,         c )), ('flrp', a, b, c), '!options->lower_flrp64'),