[all-commits] [llvm/llvm-project] d9c0b1: [SCEV] Simplify trunc to zero based on known bits

[Gil Rapaport via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: d9c0b128e3543d5d30f43019257bfd96ce4cdcd1
      https://github.com/llvm/llvm-project/commit/d9c0b128e3543d5d30f43019257bfd96ce4cdcd1
  Author: Gil Rapaport <gil.rapaport at intel.com>
  Date:   2021-01-03 (Sun, 03 Jan 2021)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp
    M llvm/test/Analysis/ScalarEvolution/trunc-simplify.ll
    M llvm/test/Transforms/LoopVectorize/dont-fold-tail-for-assumed-divisible-TC.ll

  Log Message:
  -----------
  [SCEV] Simplify trunc to zero based on known bits

Let getTruncateExpr() short-circuit to zero when the value being truncated is
known to have at least as many trailing zeros as the target type.

Differential Revision: https://reviews.llvm.org/D93973