This really only hits for bitsets with a size of a multiple of 32. We can end up with pos = -1 as a result of the ffs, which we in turn decide is a valid position (since we fall through the loop and i == 1, we end up adding 32 to it, so end up returning 31 again).
Up until recently this was largely unreachable, as the register file sizes were all 63 or 255. However with the advent of compute shaders which can restrict the number of registers, this can now happen. Signed-off-by: Ilia Mirkin <[email protected]> Cc: "12.0" <[email protected]> --- src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp index d26acb3..682c569 100644 --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp @@ -365,6 +365,12 @@ int BitSet::findFreeRange(unsigned int count) const } } } + + // If we couldn't find a position, we can have a left-over -1 in pos. Make + // sure to abort in such a case. + if (pos < 0) + return -1; + pos += i * 32; return ((pos + count) <= size) ? pos : -1; -- 2.7.3 _______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
