diff options
author | Matt Turner <[email protected]> | 2016-01-13 11:09:11 -0800 |
---|---|---|
committer | Matt Turner <[email protected]> | 2016-01-14 09:28:01 -0800 |
commit | b82e26a6a4d6baf121f44c61c862bfa79ba0d172 (patch) | |
tree | d8c97faf241b7ea0bd07ceccde1f59f5e7058986 /src/gallium/docs | |
parent | 15640ee77ae601cba33cbbc72256e55e03a363e5 (diff) |
nir: Lower bitfield_extract.
The OpenGL specifications for bitfieldExtract() says:
The result will be undefined if <offset> or <bits> is negative, or if
the sum of <offset> and <bits> is greater than the number of bits
used to store the operand.
Therefore passing bits=32, offset=0 is legal and defined in GLSL.
But the earlier SM5 ubfe/ibfe opcodes are specified to accept a bitfield width
ranging from 0-31. As such, Intel and AMD instructions read only the low 5 bits
of the width operand, making them not able to implement the GLSL-specified
behavior directly.
This commit adds ubfe/ibfe operations from SM5 and a lowering pass for
bitfield_extract to to handle the trivial case of <bits> = 32 as
bitfieldExtract:
bits > 31 ? value : bfe(value, offset, bits)
Fixes:
ES31-CTS.shader_bitfield_operation.bitfieldExtract.uvec3_0
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92595
Reviewed-by: Connor Abbott <[email protected]>
Tested-by: Marta Lofstedt <[email protected]>
Diffstat (limited to 'src/gallium/docs')
0 files changed, 0 insertions, 0 deletions