A collection of test cases, capturing the state of various
functions at various places within the pass list, and verifying
that we can restart at various passes.
gcc/testsuite/ChangeLog:
* gcc.dg/rtl/x86_64/dfinit.c: New test case.
* gcc.dg/rtl/x86_64/different-structs.c: New test case.
* gcc.dg/rtl/x86_64/final.c: New test case.
* gcc.dg/rtl/x86_64/into-cfglayout.c: New test case.
* gcc.dg/rtl/x86_64/ira.c: New test case.
* gcc.dg/rtl/x86_64/pro_and_epilogue.c: New test case.
* gcc.dg/rtl/x86_64/test-multiple-fns.c: New test case.
* gcc.dg/rtl/x86_64/test-return-const.c.after-expand.c: New test case.
* gcc.dg/rtl/x86_64/test-return-const.c.before-fwprop.c: New test case.
* gcc.dg/rtl/x86_64/test-rtl.c: New test case.
* gcc.dg/rtl/x86_64/test_1.h: New file.
* gcc.dg/rtl/x86_64/times-two.c.after-expand.c: New test case.
* gcc.dg/rtl/x86_64/times-two.c.before-df.c: New test case.
* gcc.dg/rtl/x86_64/times-two.h: New file.
* gcc.dg/rtl/x86_64/vregs.c: New test case.