[Bug tree-optimization/54855] Unnecessary duplication when performing scalar operation on vector element

[hjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54855

--- Comment #10 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> ---
Author: hjl
Date: Thu Jun 20 15:30:54 2019
New Revision: 272511

URL: https://gcc.gnu.org/viewcvs?rev=272511&root=gcc&view=rev
Log:
i386: Generate standard floating point scalar operation patterns

Standard floating point scalar operation patterns for combiner, which
preserve the rest of the vector, look like

     (vec_merge:V2DF
       (vec_duplicate:V2DF (reg:DF 87))
       (reg/v:V2DF 85 [ x ])
       (const_int 1 [0x1])]))

and

     (vec_merge:V2DF
       (vec_duplicate:V2DF
         (op:DF (vec_select:DF (reg/v:V2DF 85 [ x ])
                (parallel [ (const_int 0 [0])]))
         (reg:DF 87))
       (reg/v:V2DF 85 [ x ])
       (const_int 1 [0x1])]))

This patch adds and generates such standard floating point scalar
operation patterns for +, -, *, /, > and <.

Tested on x86-64.

gcc/

        PR target/54855
        * config/i386/i386-expand.c (ix86_expand_vector_set): Generate
        standard scalar operation pattern for V2DF.
        * config/i386/sse.md (*<sse>_vm<plusminus_insn><mode>3): New.
        (*<sse>_vm<multdiv_mnemonic><mode>3): Likewise.
        (*ieee_<ieee_maxmin><mode>3): Likewise.
        (vec_setv2df_0): Likewise.

gcc/testsuite/

        PR target/54855
        * gcc.target/i386/pr54855-1.c: New test.
        * gcc.target/i386/pr54855-2.c: Likewise.
        * gcc.target/i386/pr54855-3.c: Likewise.
        * gcc.target/i386/pr54855-4.c: Likewise.
        * gcc.target/i386/pr54855-5.c: Likewise.
        * gcc.target/i386/pr54855-6.c: Likewise.
        * gcc.target/i386/pr54855-7.c: Likewise.
        * gcc.target/i386/pr54855-8.c: Likewise.
        * gcc.target/i386/pr54855-9.c: Likewise.
        * gcc.target/i386/pr54855-10.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr54855-1.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-10.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-2.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-3.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-4.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-5.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-6.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-7.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-8.c
    trunk/gcc/testsuite/gcc.target/i386/pr54855-9.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386-expand.c
    trunk/gcc/config/i386/sse.md
    trunk/gcc/testsuite/ChangeLog