search for: expandshiftbyconst

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 Expan...

Hi Javier, > 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. I see, sorry I didn't read your email more carefully. It does look like ExpandShiftWithUnknownAmountBit is bogus - at a glance it looks like the Cmp condit...

Hi Duncan, Just wondering if you had a chance to look at the expansion. Thanks, Javier On Tue, 01 Dec 2009 20:20:14 +0100, Duncan Sands <baldrick at free.fr> wrote: > Hi Javier, > >> 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. > > I see, sorry I didn't read your email more carefully. It does look like > ExpandShiftWithUnknownAmountBit is bogus - at a glance it looks...

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