S2 doms S5? Sun On Thu, Feb 10, 2011 at 7:55 AM, Min Zhao <mzhao...@gmail.com> wrote: > > Sorry, I should NOT use v0 as an example version. For better explanation, > using the real verions in the code: > > S1: loc = 0; > S2: buffer[limit] = 33; > sym3v18 = chi (sym3v11) // buffer > sym5v19 = chi (sym5v13) // buffer scalar var -> NOT LIVE by DSE > -> LIVE by ILOAD_FOLD > S3: if (buffer[loc] != 10) > mu(sym3v18) // change to LDID (sym5v19) by ILOAD_FOLD > S4: loc = loc + 1; > S5: buffer[limit] = 32; > sym3v24 = chi (sym3v18) > sym5v25 = chi (sym5v19) // change to sym5v25 = chi (sym5v13) by > DSE > S6: if (buffer[0] == 15) > > Although sym5v19 = chi (sym5v13) is resurrected, sym5v25 = chi (sym5v13) is > still using sym5v13, instead of sym5v19. > > On Wed, Feb 9, 2011 at 2:48 PM, Sun Chan <sun.c...@gmail.com> wrote: >> >> i still don't understand why you think you can use v1, the more >> precise version, instead of zero version? This is more than just a >> versioning problem. It is a precision problem, isn't it? >> Sun >> >> On Thu, Feb 10, 2011 at 2:56 AM, Min Zhao <mzhao...@gmail.com> wrote: >> > More explanations. >> > >> > Here is the failing test case: >> > >> > S1: loc = 0; >> > >> > S2: buffer[limit] = 33; >> > >> > sym3v1 = chi (sym3v0) // buffer >> > >> > sym5v1 = chi (sym5v0) // buffer scalar var -> NOT LIVE by >> > DSE -> >> > LIVE by ILOAD_FOLD >> > >> > S3: if (buffer[loc] != 10) >> > >> > mu(sym3v1) // change to LDID (sym5v1) by ILOAD_FOLD >> > >> > S4: loc = loc + 1; >> > >> > S5: buffer[limit] = 32; >> > >> > sym3v2 = chi (sym3v1) >> > >> > sym5v2 = chi (sym5v1) // change to sym5v2 = chi (sym5v0) by >> > DSE >> > >> > S6: if (buffer[0] == 15) >> > >> > mu (sym5v2) >> > >> > ... >> > >> > >> > >> > Since there is no use of sym5v1 between S2 and S5, DSE 1) marks “sym5v1 >> > = >> > chi (sym5v0)” as NOT LIVE 2) changes the chi in S5 to sym5v2 = chi >> > (sym5v0). >> > >> > >> > >> > Later, in the Create_CODEMAP, ILOAD_FOLD is done for buffer[loc], which >> > is >> > buffer[0]. Now sym5v1 is used. ILOAD_FOLD resurrect the chi, sym5v1 = >> > chi >> > (sym5v0). But the problem is that after resurrect_chi, sym5v2 = chi >> > (sym5v0) >> > is still using sym5v0 instead of sym5v1. Thus, overlapping live range >> > problem happens. >> > >> > >> > >> > The fix is to change all appropriate uses of sym5v0 to sym5v1. > >
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