glsl: don't lower to mediump for desktop OpenGL

Desktop OpenGL ignores all precision qualifiers.

Also, the lowering pass doesn't work if precision qualifiers are not set,
which is only possible with desktop OpenGL, causing random behavior.

Reviewed-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6073>

diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
index e9130d16d254eb4686729de1cf358b8439c10612..cb206e32a499e63fea8dc0279edc7410fe7ae0b4 100644 (file)
--- a/src/compiler/glsl/glsl_parser_extras.cpp
+++ b/src/compiler/glsl/glsl_parser_extras.cpp
@@ -2249,7 +2249,8 @@ _mesa_glsl_compile_shader(struct gl_context *ctx, struct gl_shader *shader,
       &ctx->Const.ShaderCompilerOptions[shader->Stage];
 
    if (!state->error && !shader->ir->is_empty()) {
       &ctx->Const.ShaderCompilerOptions[shader->Stage];
 
    if (!state->error && !shader->ir->is_empty()) {

-      if (options->LowerPrecisionFloat16 || options->LowerPrecisionInt16)
+      if (state->es_shader &&
+          (options->LowerPrecisionFloat16 || options->LowerPrecisionInt16))

          lower_precision(options, shader->ir);
       lower_builtins(shader->ir);
       assign_subroutine_indexes(state);
          lower_precision(options, shader->ir);
       lower_builtins(shader->ir);
       assign_subroutine_indexes(state);