i965/blorp: Optimize clamping tex coords.

Each emit_cond_mov() emits a CMP of its first to arguments using the
specified conditional mod, followed by a predicated MOV of the fifth
argument into the fourth. In all four cases here, it was just
implementing MIN/MAX which we can do in a single SEL instruction.

Also reorder the instructions for a slightly better schedule.

Reviewed-by: Ian Romanick <[email protected]>

2 files changed, 22 insertions, 4 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
index 10a53dc0ac4..fc111aef3b1 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
+++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
@@ -1308,10 +1308,10 @@ brw_blorp_blit_program::clamp_tex_coords(struct brw_reg regX,
                                          struct brw_reg clampX1,
                                          struct brw_reg clampY1)
 {
-   emit_cond_mov(regX, clampX0, BRW_CONDITIONAL_L, regX, clampX0);
-   emit_cond_mov(regX, clampX1, BRW_CONDITIONAL_G, regX, clampX1);
-   emit_cond_mov(regY, clampY0, BRW_CONDITIONAL_L, regY, clampY0);
-   emit_cond_mov(regY, clampY1, BRW_CONDITIONAL_G, regY, clampY1);
+   emit_max(regX, regX, clampX0);
+   emit_max(regY, regY, clampY0);
+   emit_min(regX, regX, clampX1);
+   emit_min(regY, regY, clampY1);
 }
 
 /**
diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit_eu.h b/src/mesa/drivers/dri/i965/brw_blorp_blit_eu.h
index 8953ce83487..bfad4224a2c 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp_blit_eu.h
+++ b/src/mesa/drivers/dri/i965/brw_blorp_blit_eu.h
@@ -85,6 +85,24 @@ protected:
          new (mem_ctx) fs_inst(BRW_OPCODE_LRP, 16, dst, src1, src2, src3));
    }
 
+   inline void emit_min(const struct brw_reg& dst,
+                        const struct brw_reg& src1,
+                        const struct brw_reg& src2)
+   {
+      fs_inst *inst = new (mem_ctx) fs_inst(BRW_OPCODE_SEL, 16, dst, src1, src2);
+      inst->conditional_mod = BRW_CONDITIONAL_L;
+      insts.push_tail(inst);
+   }
+
+   inline void emit_max(const struct brw_reg& dst,
+                        const struct brw_reg& src1,
+                        const struct brw_reg& src2)
+   {
+      fs_inst *inst = new (mem_ctx) fs_inst(BRW_OPCODE_SEL, 16, dst, src1, src2);
+      inst->conditional_mod = BRW_CONDITIONAL_GE;
+      insts.push_tail(inst);
+   }
+
    inline void emit_mov(const struct brw_reg& dst, const struct brw_reg& src)
    {
       insts.push_tail(new (mem_ctx) fs_inst(BRW_OPCODE_MOV, 16, dst, src));