From 3711abd780141b84a33f393446b05a6a385200d4 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Fri, 24 Oct 2014 13:04:24 -0700 Subject: [PATCH] glsl: Store glsl_type::vector_elements and ::matrix_columns as uint8_t MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Due to the total number of bits used in the bitfield, this does not increase the size of the structure. It does, however, reduce the number of instructions required each time one of these fields is accessed. To access ::matrix_columns with the bitfield, three instructions were required: movzbl 0x9(%rdx),%eax shr %al and $0x7,%eax As a uint8_t, only one instruction is required. movzbl 0xa(%rdx),%eax These fields are accessed *a lot*. Valgrind callgrind results for a trace of Tesseract: _mesa_Uniform4fv _mesa_Uniform4f _mesa_Uniform1i Before (64-bit): 48,103,497 16,556,096 676,447 After (64-bit): 45,722,616 15,737,964 670,607 _mesa_Uniform4fv _mesa_Uniform4f _mesa_Uniform1i Before (32-bit): 61,472,611 21,051,222 821,361 After (32-bit): 57,987,421 19,872,226 811,609 Signed-off-by: Ian Romanick Reviewed-by: Brian Paul Reviewed-by: Tapani Pälli --- src/glsl/glsl_types.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/glsl/glsl_types.h b/src/glsl/glsl_types.h index 654304144e4..096f5462af4 100644 --- a/src/glsl/glsl_types.h +++ b/src/glsl/glsl_types.h @@ -153,8 +153,8 @@ struct glsl_type { * these will be 0. */ /*@{*/ - unsigned vector_elements:3; /**< 1, 2, 3, or 4 vector elements. */ - unsigned matrix_columns:3; /**< 1, 2, 3, or 4 matrix columns. */ + uint8_t vector_elements; /**< 1, 2, 3, or 4 vector elements. */ + uint8_t matrix_columns; /**< 1, 2, 3, or 4 matrix columns. */ /*@}*/ /** -- 2.30.2