[PATCH] D14035: Fix llc crash processing S/UREM for -Oz builds caused by rL250825.

[Steve King via llvm-commits]

srking created this revision.
srking added reviewers: tyomitch, rengolin.
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When taking the remainder of a value divided by a constant, visitREM() attempts to convert the REM to a longer but faster sequence of instructions.  This conversion calls combine() on a speculative DIV instruction.  Commit rL250825 may cause this combine() to return a DIVREM, corrupting nearby nodes.  Flow eventually hits unreachable().

This patch adds a test case and a check to prevent visitREM() from trying to convert the REM instruction in cases where a DIVREM is possible.

Repository:
  rL LLVM

http://reviews.llvm.org/D14035

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  test/CodeGen/Generic/urem_crash.ll

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