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nv50/ir/util: fix BitSet issues

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BitSet::allocate() is being used with the expectation that it would
leave the bitfield untouched if its size hasn't changed, however,
the function always zeroed the last word, which led to obscure bugs
with live set computation.

This also fixes BitSet::resize(), which was broken, but luckily not
being used.

Cc: "10.2 10.3" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
(cherry picked from commit b9f9e3ce03)
This commit is contained in:
Christoph Bumiller 2014-09-05 23:52:45 +02:00 • committed by Emil Velikov
parent 3f570286fc
commit f10161e477
3 changed files with 10 additions and 3 deletions
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4
src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
View file

@ -1654,6 +1654,10 @@ RegAlloc::execFunc()
ret && i <= func->loopNestingBound;
sequence = func->cfg.nextSequence(), ++i)
ret = buildLiveSets(BasicBlock::get(func->cfg.getRoot()));
// reset marker
for (ArrayList::Iterator bi = func->allBBlocks.iterator();
!bi.end(); bi.next())
BasicBlock::get(bi)->liveSet.marker = false;
if (!ret)
break;
func->orderInstructions(this->insns);

8
src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp
View file

@ -254,7 +254,9 @@ bool BitSet::resize(unsigned int nBits)
return false;
}
if (n > p)
memset(&data[4 * p + 4], 0, (n - p) * 4);
memset(&data[p], 0, (n - p) * 4);
if (nBits < size && (nBits % 32))
data[(nBits + 31) / 32 - 1] &= (1 << (nBits % 32)) - 1;
size = nBits;
return true;
@ -274,8 +276,8 @@ bool BitSet::allocate(unsigned int nBits, bool zero)
if (zero)
memset(data, 0, (size + 7) / 8);
else
if (nBits)
data[(size + 31) / 32 - 1] = 0; // clear unused bits (e.g. for popCount)
if (size % 32) // clear unused bits (e.g. for popCount)
data[(size + 31) / 32 - 1] &= (1 << (size % 32)) - 1;
return data;
}

1
src/gallium/drivers/nouveau/codegen/nv50_ir_util.h
View file

@ -484,6 +484,7 @@ public:
FREE(data);
}
// allocate will keep old data iff size is unchanged
bool allocate(unsigned int nBits, bool zero);
bool resize(unsigned int nBits); // keep old data, zero additional bits