[PATCH] propagate IR-level fast-math-flags to DAG nodes

[Sanjay Patel]

Let me ask a dumb question since I don't know any better. :)

Is the size of an SDNode so critical that we can't do the proper software engineering thing: add the flags as a member rather than riding on the bonus bits available in SubclassData? If we do that, all of the distasteful get/set and bit shifting replication disappears.

If we make a bag o' bits for the flags as in this updated patch, they'd just be single byte. As it stands, I'm showing that the sizeof(SDNode) and sizeof(SDNodeWithFlags) are both 80 bytes (building on MacOSX 10.10). Free bits!

That said, there's something very wrong with this patch now...I'm seeing *intermittent* failures on seemingly unrelated codegen regression tests. Can anyone spot the bug?


http://reviews.llvm.org/D8900

Files:
  include/llvm/CodeGen/SelectionDAG.h
  include/llvm/CodeGen/SelectionDAGNodes.h
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  lib/CodeGen/SelectionDAG/SelectionDAG.cpp
  lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
  lib/CodeGen/SelectionDAG/TargetLowering.cpp
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/PowerPC/fdiv-combine.ll

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D8900.23890.patch
Type: text/x-patch
Size: 18866 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150417/391b3ce1/attachment.bin>