JDK-7199654 : Remove LoadUI2LNode
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: hs24
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2012-09-19
  • Updated: 2013-09-04
  • Resolved: 2012-10-09
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JDK 7 JDK 8 Other
7u40Resolved 8Fixed hs24Fixed
Description
Remove LoadUI2LNode from Ideal.
Comments
I want to remove LoadUI2L node because, I think, it is wrong and we don't need it in Ideal graph, we can do the same optimization in .ad files with predicate. This node reports its memory_type() as T_LONG but it is actually reading from an integer (4 bytes) field or array element. As result of this mismatch our memory aliasing analysis and vectors construction code could be incorrect. I hit an assert I added into superword.cpp today. LoadUI2L was added as part of "6797305: Add LoadUB and LoadUI opcode class" changes: http://hg.openjdk.java.net/hsx/hotspot-main/hotspot/rev/337400e7a5dd If nobody objects I want a volunteer from our new members to do that. Thanks, Vladimir
09-10-2012
Here is new mach node definition: instruct loadUI2L(eRegL dst, memory mem, immL_32bits mask, eFlagsReg cr) %{ match(Set dst (AndL (ConvI2L (LoadI mem)) mask)); effect(KILL cr); Vladimir
09-10-2012