2016-11-17  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    PR target/77933
    * config/arm/arm.c (thumb1_expand_prologue): Distinguish between lr
    being live in the function and lr needing to be saved.  Distinguish
    between already saved pushable registers and registers to push.
    Check for LR being an available pushable register.

    gcc/testsuite/
    PR target/77933
    * gcc.target/arm/pr77933-1.c: New test.
    * gcc.target/arm/pr77933-2.c: Likewise.

From-SVN: r242559