freedreno/ir3: fragz cannot be half precision

Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
index 77d8685..bb3f66c 100644 (file)
--- a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
@@ -2428,8 +2428,14 @@ ir3_compile_shader_nir(struct ir3_compiler *compiler,
        if (so->key.half_precision) {
                for (i = 0; i < ir->noutputs; i++) {
                        struct ir3_instruction *out = ir->outputs[i];
+
                        if (!out)
                                continue;
+
+                       /* if frag shader writes z, that needs to be full precision: */
+                       if (so->outputs[i/4].slot == FRAG_RESULT_DEPTH)
+                               continue;
+
                        out->regs[0]->flags |= IR3_REG_HALF;
                        /* output could be a fanout (ie. texture fetch output)
                         * in which case we need to propagate the half-reg flag