Attachment 114800 Details for Bug 84225 – attempt to fix this issue

[patch] attempt to fix this issue

0001-glsl-detect-sampler-array-indexing-with-loop-variabl.patch (text/plain), 3.89 KB, created by Tapani Pälli on 2015-04-01 08:22:41 UTC

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Creator: Tapani Pälli

Created: 2015-04-01 08:22:41 UTC

Size: 3.89 KB

patch

obsolete

>From 6bdf999a1adcf14931325ebbd903a63e41f86541 Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Tapani=20P=C3=A4lli?= <tapani.palli@intel.com>
>Date: Wed, 1 Apr 2015 11:17:42 +0300
>Subject: [PATCH] glsl: detect sampler array indexing with loop variable WIP
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>Patch adds additional pass to array index checking, this pass
>detects if we are inside a loop and if the given array index
>references only one variable and if this variable is the loop
>induction variable.
>
>This makes is possible to allow 'constant index expression' in
>sampler arrays with OpenGL ES 2.0.
>
>Signed-off-by: Tapani PÃ¤lli <tapani.palli@intel.com>
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84225
>---
> src/glsl/ast_array_index.cpp | 98 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 98 insertions(+)
>
>diff --git a/src/glsl/ast_array_index.cpp b/src/glsl/ast_array_index.cpp
>index ecef651..e676827 100644
>--- a/src/glsl/ast_array_index.cpp
>+++ b/src/glsl/ast_array_index.cpp
>@@ -25,6 +25,61 @@
> #include "glsl_types.h"
> #include "ir.h"
> 
>+#include "ir_hierarchical_visitor.h"
>+
>+/* Class to find if there is only one variable dereference
>+ * in the traversed ir.
>+ */
>+class single_ref : public ir_hierarchical_visitor
>+{
>+public:
>+   explicit single_ref() :
>+      dref(NULL)
>+   {
>+   }
>+
>+   ir_visitor_status visit(ir_dereference_variable *ir)
>+   {
>+      /* "There can be only one." */
>+      if (dref) {
>+         dref = NULL;
>+         return visit_stop;
>+      }
>+
>+      dref = ir;
>+      return visit_continue;
>+   }
>+
>+   ir_dereference_variable *dref;
>+};
>+
>+
>+/* Class to find out if given variable is the only
>+ * variable referenced in the traversed ir.
>+ */
>+class single_var_finder : public ir_hierarchical_visitor
>+{
>+public:
>+   explicit single_var_finder(ir_variable *var) :
>+      other_vars(false),
>+      var(var)
>+   {
>+   }
>+
>+   ir_visitor_status visit(ir_dereference_variable *ir)
>+   {
>+      if (ir->variable_referenced() != var) {
>+         other_vars = true;
>+         return visit_stop;
>+      }
>+
>+      return visit_continue;
>+   }
>+
>+   bool other_vars;
>+   ir_variable *var;
>+};
>+
> void
> ast_array_specifier::print(void) const
> {
>@@ -106,6 +161,41 @@ update_max_array_access(ir_rvalue *ir, int idx, YYLTYPE *loc,
>    }
> }
> 
>+static bool
>+constant_expression_check(struct _mesa_glsl_parse_state *state,
>+                          ir_rvalue *idx)
>+{
>+   if (!state->loop_nesting_ast)
>+      return false;
>+
>+   /* First find out if idx contains only one variable dereference,
>+    * if only one then we can continue to check if this is the loop
>+    * induction variable.
>+    */
>+   single_ref sref;
>+
>+   exec_list tmp;
>+   tmp.push_head(idx);
>+   sref.run(&tmp);
>+
>+   ir_dereference_variable *dref = sref.dref;
>+
>+   if (!dref)
>+      return false;
>+
>+   /* Check if the parsed loop condition contains only single
>+    * variable reference, same as referenced by idx.
>+    */
>+   exec_list loop_cond;
>+   state->loop_nesting_ast->condition_to_hir(&loop_cond, state);
>+   single_var_finder finder(dref->variable_referenced());
>+   finder.run(&loop_cond);
>+
>+   if (finder.other_vars)
>+      return false;
>+
>+   return true;
>+}
> 
> ir_rvalue *
> _mesa_ast_array_index_to_hir(void *mem_ctx,
>@@ -226,6 +316,12 @@ _mesa_ast_array_index_to_hir(void *mem_ctx,
>        * dynamically uniform expression is undefined.
>        */
>       if (array->type->element_type()->is_sampler()) {
>+
>+         /* Check if we are indexing with a loop induction variable.
>+          */
>+         if (constant_expression_check(state, idx))
>+               goto generate_ir;
>+
> 	 if (!state->is_version(130, 100)) {
> 	    if (state->es_shader) {
> 	       _mesa_glsl_warning(&loc, state,
>@@ -247,6 +343,8 @@ _mesa_ast_array_index_to_hir(void *mem_ctx,
>       }
>    }
> 
>+generate_ir:
>+
>    /* After performing all of the error checking, generate the IR for the
>     * expression.
>     */
>-- 
>2.1.0
>

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