nir_to_tgsi: run constant folding after nir_opt_algebraic

Otherwise, an infinite loop can occur.

The first nir_opt_algebraic in the loop can optimize:
op(bcsel(a, #b, c), #d) to bcsel(a, op(b, d), op(c, d))
which (because op(b, d) is not constant folded), will be reverted by the
second nir_opt_algebraic in the loop.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Neha Bhende <bhenden@vmware.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10071>

src/gallium/auxiliary/nir/nir_to_tgsi.c

@@ -2411,6 +2411,7 @@ ntt_optimize_nir(struct nir_shader *s, struct pipe_screen *screen)
 
       NIR_PASS(progress, s, nir_copy_prop);
       NIR_PASS(progress, s, nir_opt_algebraic);
+      NIR_PASS(progress, s, nir_opt_constant_folding);
       NIR_PASS(progress, s, nir_opt_remove_phis);
       NIR_PASS(progress, s, nir_opt_conditional_discard);
       NIR_PASS(progress, s, nir_opt_dce);