r300/compiler: Enable presubtract sources

The r300 compiler can now emit instructions that select from the presubtract
source.  A peephole optimization has been added to convert instructions like:
ADD Temp[0].x, none.1, -Temp[1].x into the INV (1 - src0) presubtract
operation.

2 files changed, 2 insertions, 0 deletions

diff --git a/src/gallium/drivers/r300/r300_fs.c b/src/gallium/drivers/r300/r300_fs.c
index b9f4d77dea7..b8dab88ef09 100644
--- a/src/gallium/drivers/r300/r300_fs.c
+++ b/src/gallium/drivers/r300/r300_fs.c
@@ -387,6 +387,7 @@ static void r300_translate_fragment_shader(
     compiler.Base.is_r500 = r300->screen->caps.is_r500;
     compiler.Base.disable_optimizations = DBG_ON(r300, DBG_NO_OPT);
     compiler.Base.has_half_swizzles = TRUE;
+    compiler.Base.has_presub = TRUE;
     compiler.Base.max_temp_regs = compiler.Base.is_r500 ? 128 : 32;
     compiler.Base.max_constants = compiler.Base.is_r500 ? 256 : 32;
     compiler.Base.max_alu_insts = compiler.Base.is_r500 ? 512 : 64;
diff --git a/src/gallium/drivers/r300/r300_vs.c b/src/gallium/drivers/r300/r300_vs.c
index 22c94adbda0..e2b9af9d018 100644
--- a/src/gallium/drivers/r300/r300_vs.c
+++ b/src/gallium/drivers/r300/r300_vs.c
@@ -208,6 +208,7 @@ void r300_translate_vertex_shader(struct r300_context *r300,
     compiler.Base.is_r500 = r300->screen->caps.is_r500;
     compiler.Base.disable_optimizations = DBG_ON(r300, DBG_NO_OPT);
     compiler.Base.has_half_swizzles = FALSE;
+    compiler.Base.has_presub = FALSE;
     compiler.Base.max_temp_regs = 32;
     compiler.Base.max_constants = 256;
     compiler.Base.max_alu_insts = r300->screen->caps.is_r500 ? 1024 : 256;