Dhruv Chawla 20ae2d200d [InstCombine] Generalize foldAndOrOfICmpEqZeroAndICmp ...

This patch generalizes the fold implemented by foldAndOrOfICmpEqZeroAndICmp,
which are:

(icmp eq X, 0) | (icmp ult Other, X) -> (icmp ule Other, X-1)
(icmp ne X, 0) & (icmp uge Other, X) -> (icmp ugt Other, X-1)

to the following:

(icmp eq X, C) | (icmp ult Other, (X - C)) -> (icmp ule Other, (X - (C + 1)))
(icmp ne X, C) & (icmp uge Other, (X - C)) -> (icmp ugt Other, (X - (C + 1)))

The function foldAndOrOfICmpEqZeroAndICmp is also renamed to
foldAndOrOfICmpEqConstantAndICmp to reflect the changes.

Proofs: https://alive2.llvm.org/ce/z/yXGv6q

Fixes #63749.

Differential Revision: https://reviews.llvm.org/D154937

2023-07-12 11:13:37 +05:30

184 KiB

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