Mesa (10.2): nv50/ir/util: fix BitSet issues

[Emil Velikov]

Module: Mesa
Branch: 10.2
Commit: 996eaf37d69aff604265161d004f3b1c08266326
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=996eaf37d69aff604265161d004f3b1c08266326

Author: Christoph Bumiller <e0425955 at student.tuwien.ac.at>
Date:   Fri Sep  5 23:52:45 2014 +0200

nv50/ir/util: fix BitSet issues

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 at lists.freedesktop.org>
Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>
(cherry picked from commit b9f9e3ce03dbd8d044a72a00e1e8856a500b5f72)

---

 src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp   |    4 ++++
 src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp |    8 +++++---
 src/gallium/drivers/nouveau/codegen/nv50_ir_util.h   |    1 +
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
index b284081..f2a8b55 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
@@ -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);
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp
index 8959777..d26acb3 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_util.cpp
@@ -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;
 }
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_util.h b/src/gallium/drivers/nouveau/codegen/nv50_ir_util.h
index a4ea9d9..fa2c480 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_util.h
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_util.h
@@ -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