search for: v1176

On Feb 2, 2009, at 12:12 PM, David Greene wrote: > On Monday 02 February 2009 13:14, Evan Cheng wrote: > >> I am sorry I don't really follow it. Is this what you are describing? >> >> %v1177 = undef >> ... >> loop: >> ... >> %v1176 = op ... >> = %v1177 >> %v1177 = %v1176 >> jmp loop >> >> Why is not safe to coalesce the 2 registers? > > Not quite. The original code is: > > %v1177 = undef > %v1645 = ... > loop: > %v1176 = %v1645 > ... > = %v1176 >...

...9, at 12:12 PM, David Greene wrote: > > On Monday 02 February 2009 13:14, Evan Cheng wrote: > >> I am sorry I don't really follow it. Is this what you are describing? > >> > >> %v1177 = undef > >> ... > >> loop: > >> ... > >> %v1176 = op ... > >> = %v1177 > >> %v1177 = %v1176 > >> jmp loop > >> > >> Why is not safe to coalesce the 2 registers? > > > > Not quite. The original code is: > > > > %v1177 = undef > > %v1645 = ... > > lo...

...;> On Monday 02 February 2009 13:14, Evan Cheng wrote: >>>> I am sorry I don't really follow it. Is this what you are >>>> describing? >>>> >>>> %v1177 = undef >>>> ... >>>> loop: >>>> ... >>>> %v1176 = op ... >>>> = %v1177 >>>> %v1177 = %v1176 >>>> jmp loop >>>> >>>> Why is not safe to coalesce the 2 registers? >>> >>> Not quite. The original code is: >>> >>> %v1177 = undef >>&g...

On Monday 02 February 2009 13:14, Evan Cheng wrote: > I am sorry I don't really follow it. Is this what you are describing? > > %v1177 = undef > ... > loop: > ... > %v1176 = op ... > = %v1177 > %v1177 = %v1176 > jmp loop > > Why is not safe to coalesce the 2 registers? Not quite. The original code is: %v1177 = undef %v1645 = ... loop: %v1176 = %v1645 ... = %v1176 = %v1177 %v1645 = op ... %v1177 = %v1176 jmp loop We can't c...

...#39;s because of this value that we cannot > coalesce > %reg1177 and %reg1176. It's because of this value that %reg1177 is > always one > value "behind" %reg1176. I am sorry I don't really follow it. Is this what you are describing? %v1177 = undef ... loop: ... %v1176 = op ... = %v1177 %v1177 = %v1176 jmp loop Why is not safe to coalesce the 2 registers? Evan > > > Now, if there's some other way to tell the coalescer that the > coalescing is > illegal, that's fine. I don't care about the undef value number >...

...09 13:14, Evan Cheng wrote: >>>>> I am sorry I don't really follow it. Is this what you are >>>>> describing? >>>>> >>>>> %v1177 = undef >>>>> ... >>>>> loop: >>>>> ... >>>>> %v1176 = op ... >>>>> = %v1177 >>>>> %v1177 = %v1176 >>>>> jmp loop >>>>> >>>>> Why is not safe to coalesce the 2 registers? >>>> >>>> Not quite. The original code is: >>>> >&gt...

On Monday 02 February 2009 23:55, Evan Cheng wrote: > >> Think about what will happen the 2nd iteration.  %v1177 will have > >> the value of > >> %v1645 which is wrong.  This is because %v1176 in bb74 will be > >> replaced with > >> %v1177.  That's incorrect. > > > > Ok, right. The trick to fixing is to make sure the valno of the def of > > v1177 hasPHIKill to true and make sure the coalescer checks it. What does hasPHIKill mean, what are the cons...

On Feb 5, 2009, at 5:30 PM, David Greene wrote: > On Monday 02 February 2009 23:55, Evan Cheng wrote: > >>>> Think about what will happen the 2nd iteration. %v1177 will have >>>> the value of >>>> %v1645 which is wrong. This is because %v1176 in bb74 will be >>>> replaced with >>>> %v1177. That's incorrect. >>> >>> Ok, right. The trick to fixing is to make sure the valno of the >>> def of >>> v1177 hasPHIKill to true and make sure the coalescer checks it. > > What...

On Friday 30 January 2009 16:54, Evan Cheng wrote: > I don't have the whole context to understand why you think this is a > bug. An implicit_def doesn't actually define any value. So we don't > care if a live interval overlaps live ranges defined by an implicit_def. It's a bug because the coalerscer does illegal coaescing. Our last episode left us here: bb134: 2696

On Jan 30, 2009, at 1:52 PM, David Greene wrote: > On Friday 30 January 2009 15:10, David Greene wrote: > >> This still looks correct. The coalescer then says: >> >> 4360 %reg1177<def> = FsMOVAPSrr %reg1176<kill> ; srcLine 0 >> Inspecting %reg1176,0 = [2702,4362:0) 0 at 2702-(4362) and >> %reg1177,0 = >>