[Bug middle-end/42972] Very bad bit field code

[steven at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42972

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2012-03-18 12:45:53         |2019-3-6

--- Comment #7 from Steven Bosscher <steven at gcc dot gnu.org> ---
GCC 8.2 (still -march=armv5te -O3):

        .arch armv5te
        .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 34, 0
        .eabi_attribute 18, 4
        .file   "example.c"
        .text
        .align  2
        .global func
        .syntax unified
        .arm
        .fpu softvfp
        .type   func, %function
func:
        mov     ip, #0
.L9:
        ldrb    r3, [r0]        @ zero_extendqisi2
        add     ip, ip, #1
        tst     r3, #1
        beq     .L16
        str     lr, [sp, #-4]!
.L10:
        ldr     r3, [r0]
        add     lr, r2, r3, lsr #1
        and     r3, r3, #1
        orr     r3, r3, lr, lsl #1
        str     r3, [r0]
.L2:
        cmp     ip, r1
        add     r0, r0, #4
        ldrge   pc, [sp], #4
        ldrb    r3, [r0]        @ zero_extendqisi2
        add     ip, ip, #1
        tst     r3, #1
        beq     .L2
        b       .L10
.L16:
        cmp     ip, r1
        add     r0, r0, #4
        blt     .L9
        bx      lr
        .size   func, .-func
        .ident  "GCC: (GNU) 8.2.0"
        .section        .note.GNU-stack,"",%progbits