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e5741d7263
bounds, step, and loop induction variable.
Summary: This PR extends the loop object with more utilities to get loop
bounds, step, and loop induction variable. There already exists passes
which try to obtain the loop induction variable in their own pass, e.g.
loop interchange. It would be useful to have a common area to get these
information.
/// Example:
/// for (int i = lb; i < ub; i+=step)
/// <loop body>
/// --- pseudo LLVMIR ---
/// beforeloop:
/// guardcmp = (lb < ub)
/// if (guardcmp) goto preheader; else goto afterloop
/// preheader:
/// loop:
/// i1 = phi[{lb, preheader}, {i2, latch}]
/// <loop body>
/// i2 = i1 + step
/// latch:
/// cmp = (i2 < ub)
/// if (cmp) goto loop
/// exit:
/// afterloop:
///
/// getBounds
/// getInitialIVValue --> lb
/// getStepInst --> i2 = i1 + step
/// getStepValue --> step
/// getFinalIVValue --> ub
/// getCanonicalPredicate --> '<'
/// getDirection --> Increasing
/// getInductionVariable --> i1
/// getAuxiliaryInductionVariable --> {i1}
/// isCanonical --> false
Reviewers: kbarton, hfinkel, dmgreen, Meinersbur, jdoerfert, syzaara,
fhahn
Reviewed By: kbarton
Subscribers: tvvikram, bmahjour, etiotto, fhahn, jsji, hiraditya,
llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D60565
llvm-svn: 362609