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authorBryan Cain <[email protected]>2011-08-27 18:32:58 -0500
committerKenneth Graunke <[email protected]>2011-08-31 12:02:18 -0700
commit478034f34a59969103237eb78bc82f9e70fe81c2 (patch)
tree124922638fd8c7f981331cc6dbb5e1ceda6bd07f /src/mesa/drivers
parent87679e2ea10836d89f47a37b8e94cce0d319622e (diff)
glsl: Use a separate div_to_mul_rcp lowering flag for integers.
Using multiply and reciprocal for integer division involves potentially lossy floating point conversions. This is okay for older GPUs that represent integers as floating point, but undesirable for GPUs with native integer division instructions. TGSI, for example, has UDIV/IDIV instructions for integer division, so it makes sense to handle this directly. Likewise for i965. Reviewed-by: Ian Romanick <[email protected]> Signed-off-by: Bryan Cain <[email protected]> Signed-off-by: Kenneth Graunke <[email protected]>
Diffstat (limited to 'src/mesa/drivers')
-rw-r--r--src/mesa/drivers/dri/i965/brw_shader.cpp1
1 files changed, 1 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
index 0a21094708b..a6ed810a16e 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.cpp
+++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
@@ -100,6 +100,7 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
lower_instructions(shader->ir,
MOD_TO_FRACT |
DIV_TO_MUL_RCP |
+ INT_DIV_TO_MUL_RCP |
SUB_TO_ADD_NEG |
EXP_TO_EXP2 |
LOG_TO_LOG2);