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Hello, I'm working in adding support for 64-bit integers to my target. I'm using LLVM to decompose the 64-bit integer operations by using 32-bit registers wherever possible and emulating support where not. When looking at the bit shift decomposition I saw what seems to be a bug in the implementation. The affected function is ExpandShiftWithUnknownAmountBit in LegalizeIntegerTypes.cpp.

Hi Javier, > The problem is the implementation of the expansion. Perhaps an example > can help illustrate better. Take the case of a 64-bit integer shifted > left by say 6 bits and is decomposed using 32-bit registers. Because 6 > is less than the 32 (the register size) the resulting low part should be > equal to the source low part shifted left by 6 bits. The current >

Hi Duncan, The problem is the implementation of the expansion. Perhaps an example can help illustrate better. Take the case of a 64-bit integer shifted left by say 6 bits and is decomposed using 32-bit registers. Because 6 is less than the 32 (the register size) the resulting low part should be equal to the source low part shifted left by 6 bits. The current implementation places a zero

On Mon, Nov 30, 2009 at 7:22 PM, Javier Martinez <javier at jmartinez.org> wrote: > Hello, > > I'm working in adding support for 64-bit integers to my target. I'm using > LLVM to decompose the 64-bit integer operations by using 32-bit registers > wherever possible and emulating support where not. When looking at the bit > shift decomposition I saw what seems to be a

Duncan, It seems that the code you pasted came from the function ExpandShiftByConstant and indeed it looks correct. In my example I used 6 as the shift amount but forgot to mention that it's stored in a register. Otherwise ExpandShiftWithUnknownAmountBit wouldn't get called. Below is the execution of DAGTypeLegalizer::ExpandIntRes_Shift() using my example showing how

On Wed, May 20, 2009 at 4:55 PM, Dan Gohman <gohman at apple.com> wrote: > Can you explain why you chose the approach of using a new pass? > I pictured removing LegalizeDAG's type legalization code would > mostly consist of finding all the places that use TLI.getTypeAction > and just deleting code for handling its Expand and Promote. Are you > anticipating something more

On May 20, 2009, at 1:34 PM, Eli Friedman wrote: > On Wed, May 20, 2009 at 1:19 PM, Eli Friedman > <eli.friedman at gmail.com> wrote: > >> Per subject, this patch adding an additional pass to handle vector >> >> operations; the idea is that this allows removing the code from >> >> LegalizeDAG that handles illegal types, which should be a significant

On Wed, May 20, 2009 at 5:26 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Wed, May 20, 2009 at 4:55 PM, Dan Gohman <gohman at apple.com> wrote: >> Can you explain why you chose the approach of using a new pass? >> I pictured removing LegalizeDAG's type legalization code would >> mostly consist of finding all the places that use TLI.getTypeAction