llvm/test/Transforms/LoopStrengthReduce
Wei Mi 3e13826e61 [LSR] Canonicalize formula and put recursive Reg related with current loop in ScaledReg.
After rL294814, LSR formula can have multiple SCEVAddRecExprs inside of its BaseRegs.
Previous canonicalization will swap the first SCEVAddRecExpr in BaseRegs with ScaledReg.
But now we want to swap the SCEVAddRecExpr Reg related with current loop with ScaledReg.
Otherwise, we may generate code like this: RegA + lsr.iv + RegB, where loop invariant
parts RegA and RegB are not grouped together and cannot be promoted outside of loop.
With this patch, it will ensure lsr.iv to be generated later in the expr:
RegA + RegB + lsr.iv, so that RegA + RegB can be promoted outside of loop.

Differential Revision: https://reviews.llvm.org/D26781


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295884 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-22 21:47:08 +00:00
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