Ryan Taylor
2015-Jan-27 20:16 UTC
[LLVMdev] Making a CopyToReg/CopyFromReg into a zext/sext?
I have a CopyToReg that is copying from different size types, what's the best way to change that to a zext or sext node based on signed or unsigned? I'm fairly unfamiliar with SelectionDAG process (outside of the docs on llvm website). It seems like I should be able to insert a custom hook using the register class to identify the type, potentially in ISelDAGToDag.cpp or is there a better place for this to be done? Thanks. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150127/4f69073d/attachment.html>
Matt Arsenault
2015-Jan-27 20:22 UTC
[LLVMdev] Making a CopyToReg/CopyFromReg into a zext/sext?
On 01/27/2015 12:16 PM, Ryan Taylor wrote:> I have a CopyToReg that is copying from different size types, what's > the best way to change that to a zext or sext node based on signed or > unsigned? > > I'm fairly unfamiliar with SelectionDAG process (outside of the docs > on llvm website). > > It seems like I should be able to insert a custom hook using the > register class to identify the type, potentially in ISelDAGToDag.cpp > or is there a better place for this to be done? > > Thanks. >It sounds to me like you are looking for the AssertSext / AssertZext nodes -Matt -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150127/7eb003f4/attachment.html>
Ryan Taylor
2015-Jan-27 20:28 UTC
[LLVMdev] Making a CopyToReg/CopyFromReg into a zext/sext?
Thanks for getting back to me. So those nodes record if the type has already been expanded from a narrower type. Can you elaborate how I could use these to help? Again, I'm pretty unfamiliar with the SDNodes. Thanks. On Tue, Jan 27, 2015 at 3:22 PM, Matt Arsenault <Matthew.Arsenault at amd.com> wrote:> On 01/27/2015 12:16 PM, Ryan Taylor wrote: > > I have a CopyToReg that is copying from different size types, what's the > best way to change that to a zext or sext node based on signed or unsigned? > > I'm fairly unfamiliar with SelectionDAG process (outside of the docs on > llvm website). > > It seems like I should be able to insert a custom hook using the > register class to identify the type, potentially in ISelDAGToDag.cpp or is > there a better place for this to be done? > > Thanks. > > > It sounds to me like you are looking for the AssertSext / AssertZext nodes > > -Matt >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150127/5e0b18d4/attachment.html>
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