[Bug rtl-optimization/114243] [13/14/15 Regression][avr] -fsplit-wide-types bloats code by more than 50%

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114243

--- Comment #4 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Created attachment 58483
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58483&action=edit
sfmode.c: C test case

This is a test case with simpler functions like

float add2 (float a, float b)
{
    return a + b;
}

v8 compiles this with -Os -dp to:

add2:
        rcall __addsf3   ;  9   [c=24 l=1]  call_value_insn/1
        ret              ;  21  [c=0 l=1]  return

but the current compiler does:

add2:
        push r4          ;  76  [c=4 l=1]  pushqi1/0
        push r5          ;  77  [c=4 l=1]  pushqi1/0
        push r6          ;  78  [c=4 l=1]  pushqi1/0
        push r7          ;  79  [c=4 l=1]  pushqi1/0
        push r8          ;  80  [c=4 l=1]  pushqi1/0
        push r9          ;  81  [c=4 l=1]  pushqi1/0
        push r10                 ;  82  [c=4 l=1]  pushqi1/0
        push r11                 ;  83  [c=4 l=1]  pushqi1/0
        push r12                 ;  84  [c=4 l=1]  pushqi1/0
        push r13                 ;  85  [c=4 l=1]  pushqi1/0
        push r14                 ;  86  [c=4 l=1]  pushqi1/0
        push r15                 ;  87  [c=4 l=1]  pushqi1/0
/* prologue: function */
/* frame size = 0 */
/* stack size = 12 */
.L__stack_usage = 12
        mov r4,r18       ;  61  [c=4 l=1]  movqi_insn/0
        mov r5,r19       ;  62  [c=4 l=1]  movqi_insn/0
        mov r6,r20       ;  63  [c=4 l=1]  movqi_insn/0
        mov r7,r21       ;  64  [c=4 l=1]  movqi_insn/0
        mov r21,r7       ;  65  [c=4 l=4]  *movsf/0
        mov r20,r6
        mov r19,r5
        mov r18,r4
        mov r8,r22       ;  66  [c=4 l=1]  movqi_insn/0
        mov r9,r23       ;  67  [c=4 l=1]  movqi_insn/0
        mov r10,r24      ;  68  [c=4 l=1]  movqi_insn/0
        mov r11,r25      ;  69  [c=4 l=1]  movqi_insn/0
        mov r25,r11      ;  70  [c=4 l=4]  *movsf/0
        mov r24,r10
        mov r23,r9
        mov r22,r8
        rcall __addsf3   ;  9   [c=24 l=1]  call_value_insn/1
        mov r12,r22      ;  71  [c=4 l=1]  movqi_insn/0
        mov r13,r23      ;  72  [c=4 l=1]  movqi_insn/0
        mov r14,r24      ;  73  [c=4 l=1]  movqi_insn/0
        mov r15,r25      ;  74  [c=4 l=1]  movqi_insn/0
        mov r25,r15      ;  75  [c=4 l=4]  *movsf/0
        mov r24,r14
        mov r23,r13
        mov r22,r12
/* epilogue start */
        pop r15          ;  90  [c=4 l=1]  popqi
        pop r14          ;  91  [c=4 l=1]  popqi
        pop r13          ;  92  [c=4 l=1]  popqi
        pop r12          ;  93  [c=4 l=1]  popqi
        pop r11          ;  94  [c=4 l=1]  popqi
        pop r10          ;  95  [c=4 l=1]  popqi
        pop r9           ;  96  [c=4 l=1]  popqi
        pop r8           ;  97  [c=4 l=1]  popqi
        pop r7           ;  98  [c=4 l=1]  popqi
        pop r6           ;  99  [c=4 l=1]  popqi
        pop r5           ;  100 [c=4 l=1]  popqi
        pop r4           ;  101 [c=4 l=1]  popqi
        ret              ;  102 [c=0 l=1]  return_from_epilogue