Rewrite atan2(y,x) to cover (+/-)INF values.
This fixes several test cases in Vulkan CTS
(dEQP-VK.glsl.builtin.precision.atan2.*)
v2: do not flush denorms to 0 (jasuarez)
---
src/compiler/spirv/vtn_glsl450.c | 48 +++++++++++++++++++++++++++++++++++-----
1 file changed, 42 insertions(+), 6 deletions(-)
diff --git a/src/compiler/spirv/vtn_glsl450.c b/src/compiler/spirv/vtn_glsl450.c
index 0d32fddbef..d52a22c0c3 100644
--- a/src/compiler/spirv/vtn_glsl450.c
+++ b/src/compiler/spirv/vtn_glsl450.c
@@ -299,18 +299,47 @@ build_atan(nir_builder *b, nir_ssa_def *y_over_x)
return nir_fmul(b, tmp, nir_fsign(b, y_over_x));
}
+/*
+ * Computes atan2(y,x)
+ */
static nir_ssa_def *
build_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
{
nir_ssa_def *zero = nir_imm_float(b, 0.0f);
-
- /* If |x| >= 1.0e-8 * |y|: */
- nir_ssa_def *condition =
- nir_fge(b, nir_fabs(b, x),
- nir_fmul(b, nir_imm_float(b, 1.0e-8f), nir_fabs(b, y)));
+ nir_ssa_def *inf = nir_imm_float(b, INFINITY);
+ nir_ssa_def *minus_inf = nir_imm_float(b, -INFINITY);
+ nir_ssa_def *m_3_pi_4 = nir_fmul(b, nir_imm_float(b, 3.0f),
+ nir_imm_float(b, M_PI_4f));
+
+ /* if y == +-INF */
+ nir_ssa_def *y_is_inf = nir_feq(b, nir_fabs(b, y), inf);
+
+ /* if x == +-INF */
+ nir_ssa_def *x_is_inf = nir_feq(b, nir_fabs(b, x), inf);
+
+ /* Case: y is +-INF */
+ nir_ssa_def *y_is_inf_then =
+ nir_fmul(b, nir_fsign(b, y),
+ nir_bcsel(b, nir_feq(b, x, inf),
+ nir_imm_float(b, M_PI_4f),
+ nir_bcsel(b, nir_feq(b, x, minus_inf),
+ m_3_pi_4,
+ nir_imm_float(b, M_PI_2f))));
+
+ /* Case: x is +-INF */
+ nir_ssa_def *x_is_inf_then =
+ nir_fmul(b, nir_fsign(b, y),
+ nir_bcsel(b, nir_feq(b, x, inf),
+ zero,
+ nir_imm_float(b, M_PIf)));
+
+ /* If x > 0 */
+ nir_ssa_def *x_not_zero =
+ nir_fne(b, x, zero);
/* Then...call atan(y/x) and fix it up: */
nir_ssa_def *atan1 = build_atan(b, nir_fdiv(b, y, x));
+
nir_ssa_def *r_then =
nir_bcsel(b, nir_flt(b, x, zero),
nir_fadd(b, atan1,
@@ -323,7 +352,14 @@ build_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
nir_ssa_def *r_else =
nir_fmul(b, nir_fsign(b, y), nir_imm_float(b, M_PI_2f));
- return nir_bcsel(b, condition, r_then, r_else);
+ /* Everything together */
+ return nir_bcsel(b, y_is_inf,
+ y_is_inf_then,
+ nir_bcsel(b, x_is_inf,
+ x_is_inf_then,
+ nir_bcsel(b, x_not_zero,
+ r_then,
+ r_else)));
}
static nir_ssa_def *
--
2.11.0
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