Mesa (master): i965: Flatten if-statements beyond depth 16 on pre-gen6.
Kenneth Graunke
kwg at kemper.freedesktop.org
Mon Dec 27 09:00:33 UTC 2010
Module: Mesa
Branch: master
Commit: 634a7dce9c1d9e4a8576ff8197c8adaea7e9ddd1
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=634a7dce9c1d9e4a8576ff8197c8adaea7e9ddd1
Author: Kenneth Graunke <kenneth at whitecape.org>
Date: Mon Dec 27 00:40:26 2010 -0800
i965: Flatten if-statements beyond depth 16 on pre-gen6.
Gen4 and Gen5 hardware can have a maximum supported nesting depth of 16.
Previously, shaders with control flow nested 17 levels deep would
cause a driver assertion or segmentation fault.
Gen6 (Sandybridge) hardware no longer has this restriction.
Fixes fd.o bug #31967.
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 2de81b2..1c6ead5 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -89,6 +89,9 @@ brw_compile_shader(struct gl_context *ctx, struct gl_shader *shader)
GLboolean
brw_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
{
+ struct brw_context *brw = brw_context(ctx);
+ struct intel_context *intel = &brw->intel;
+
struct brw_shader *shader =
(struct brw_shader *)prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
if (shader != NULL) {
@@ -107,6 +110,13 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
SUB_TO_ADD_NEG |
EXP_TO_EXP2 |
LOG_TO_LOG2);
+
+ /* Pre-gen6 HW can only nest if-statements 16 deep. Beyond this,
+ * if-statements need to be flattened.
+ */
+ if (intel->gen < 6)
+ lower_if_to_cond_assign(shader->ir, 16);
+
do_lower_texture_projection(shader->ir);
brw_do_cubemap_normalize(shader->ir);
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