ir_to_mesa: Don't forget to run the Mesa IR optimization passes.

With how we generate assignments, the trivial copy propagation in it
is really important, and some drivers will really want the register
allocation, too.

src/mesa/shader/ir_to_mesa.cpp

@@ -44,6 +44,7 @@
 extern "C" {
 #include "main/mtypes.h"
 #include "shader/prog_instruction.h"
+#include "shader/prog_optimize.h"
 #include "shader/prog_print.h"
 #include "shader/program.h"
 #include "shader/prog_uniform.h"
@@ -1675,6 +1676,10 @@ get_mesa_program(GLcontext *ctx, void *mem_ctx, struct gl_shader *shader)
 
    _mesa_reference_program(ctx, &shader->Program, prog);
 
+   if ((ctx->Shader.Flags & GLSL_NO_OPT) == 0) {
+      _mesa_optimize_program(ctx, prog);
+   }
+
    return prog;
 }