Wojciech Matyjewicz e3320a1bcc Fix PR1798 - an error in the evaluation of SCEVAddRecExpr at an ... arbitrary iteration. The patch: 1) changes SCEVSDivExpr into SCEVUDivExpr, 2) replaces PartialFact() function with BinomialCoefficient(); the computations (essentially, the division) in BinomialCoefficient() are performed with the apprioprate bitwidth necessary to avoid overflow; unsigned division is used instead of the signed one. Computations in BinomialCoefficient() require support from the code generator for APInts. Currently, we use a hack rounding up the neccessary bitwidth to the nearest power of 2. The hack is easy to turn off in future. One remaining issue: we assume the divisor of the binomial coefficient formula can be computed accurately using 16 bits. It means we can handle AddRecs of length up to 9. In future, we should use APInts to evaluate the divisor. Thanks to Nicholas for cooperation! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46955 91177308-0d34-0410-b5e6-96231b3b80d8		2008-02-11 11:03:14 +00:00
..
Andersens	Create nodes for inline asm so that we don't crash looking for the node later.	2007-11-22 03:07:37 +00:00
BasicAA	Teach basicaa that 'byval' arguments define a new memory location that	2008-01-24 18:00:32 +00:00
Dominators	update for new domtree dump format	2007-08-06 06:17:08 +00:00
GlobalsModRef	Ding dong, the DoesntAccessMemoryFns and	2007-11-23 19:30:27 +00:00
LoadVN	Ding dong, the DoesntAccessMemoryFns and	2007-11-23 19:30:27 +00:00
LoopInfo	Convert .cvsignore files	2007-06-29 16:35:07 +00:00
ScalarEvolution	Fix PR1798 - an error in the evaluation of SCEVAddRecExpr at an	2008-02-11 11:03:14 +00:00