Request for reviews (XS): 6876037: CTW fails jdk7/hotspot/src/share/vm/opto/type.cpp:2055. assert(bits,"Use TypePtr for NULL")

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/6876037/webrev

Fixed 6876037: CTW fails jdk7/hotspot/src/share/vm/opto/type.cpp:2055. assert(bits,"Use TypePtr for NULL")

Missing 0 value check in TypeRawPtr::add_offset().

CastX2P node in address expression for unsafe memory operation
AddP(top, (CastX2P(SubI(3, loop_phi)), long) transformed into
AddP(top, ConP#3, SubI(0, loop_phi)):

for (int idx = 0; idx < 4; idx++) {
   unsafe.putByte(bufptr + (3-idx), b);

After loop full unroll this expression transformed
into AddP(top, ConP#3, -3). We hit assert during type
calculation for this node.