From 18d11c998940d4228ce0f5057042a885f1aa65af Mon Sep 17 00:00:00 2001 From: Ilia Mirkin Date: Tue, 31 May 2016 00:33:50 -0400 Subject: [PATCH] nv50/ir: fix error finding free element in bitset in some situations 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 Cc: "12.0" --- 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 d26acb304bc..682c5690624 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; -- 2.30.2