CELL: two-sided stencil fixes

With these changes, the tests/stencil_twoside test now works.

- Eliminate blending from the stencil_twoside test, as it produces an
  unneeded dependency on having blending working

- The spe_splat() function will now work if the register being splatted
  and the destination register are the same

- Separate fragment code generated for front-facing and back-facing
  fragments.  Often these are the same; if two-sided stenciling is on,
  they can be different.  This is easier and faster than generating
  code that does both tests and merges the results.

- Fixed a cut/paste bug where if the back Z-pass stencil operation
  were different from all the other operations, the back Z-fail
  results were incorrect.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/gallium/auxiliary/rtasm/rtasm_ppc_spe.c b/src/gallium/auxiliary/rtasm/rtasm_ppc_spe.c
index f8568f690b7..1bd9f1c8dd0 100644
--- a/src/gallium/auxiliary/rtasm/rtasm_ppc_spe.c
+++ b/src/gallium/auxiliary/rtasm/rtasm_ppc_spe.c
@@ -958,9 +958,12 @@ spe_compare_greater_uint(struct spe_function *p, unsigned rT, unsigned rA, unsig
 void
 spe_splat(struct spe_function *p, unsigned rT, unsigned rA)
 {
+   /* Use a temporary, just in case rT == rA */
+   unsigned int tmp_reg = spe_allocate_available_register(p);
    /* Duplicate bytes 0, 1, 2, and 3 across the whole register */
-   spe_ila(p, rT, 0x00010203);
-   spe_shufb(p, rT, rA, rA, rT);
+   spe_ila(p, tmp_reg, 0x00010203);
+   spe_shufb(p, rT, rA, rA, tmp_reg);
+   spe_release_register(p, tmp_reg);
 }