[Bug target/49526] New: ARM missed optimization: SMMUL instruction

["siarhei.siamashka at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49526

           Summary: ARM missed optimization: SMMUL instruction
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: siarhei.siamashka@gmail.com


$ cat test.c

int smmul(int a, int b) { return ((long long)a * b) >> 32; }

$ arm-none-linux-gnueabi-gcc -O2 -S -mcpu=cortex-a8 test.c
$ cat test.s
        .cpu cortex-a8
        .fpu softvfp
        .eabi_attribute 20, 1
        .eabi_attribute 21, 1
        .eabi_attribute 23, 3
        .eabi_attribute 24, 1
        .eabi_attribute 25, 1
        .eabi_attribute 26, 2
        .eabi_attribute 30, 2
        .eabi_attribute 18, 4
        .file   "test.c"
        .text
        .align  2
        .global smmul
        .type   smmul, %function
smmul:
        @ args = 0, pretend = 0, frame = 0
        @ frame_needed = 0, uses_anonymous_args = 0
        @ link register save eliminated.
        smull   r0, r1, r0, r1
        mov     r0, r1
        bx      lr
        .size   smmul, .-smmul
        .ident  "GCC: (GNU) 4.7.0 20110624 (experimental)"
        .section        .note.GNU-stack,"",%progbits