[Bug rtl-optimization/54555] (set (REGX) (CONST_INT B)) -> (set (STRICT_LOW_PART (REGX)) (CONST_INT B)) is pessimising

[schwab at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54555

--- Comment #2 from Andreas Schwab <schwab at gcc dot gnu.org> ---
Author: schwab
Date: Wed Jun 18 10:37:14 2014
New Revision: 211777

URL: https://gcc.gnu.org/viewcvs?rev=211777&root=gcc&view=rev
Log:
Use strict_low_part for loading a constant only if it is cheaper

    PR rtl-optimization/54555
    * postreload.c (move2add_use_add2_insn): Substitute
    STRICT_LOW_PART only if it is cheaper.

testsuite/:
    PR rtl-optimization/54555
    * gcc.target/m68k/pr54555.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/m68k/pr54555.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/postreload.c
    trunk/gcc/testsuite/ChangeLog