JIT: Duplicate function epilogs may be generated

Start with the linked Godbolt reproduction and compare the generated G_M43597_IG05 and G_M43597_IG07 epilogs in the assembly output. Trace the JIT code-generation path responsible for these return blocks and verify the result on the supplied TwoEpilogs example. Done means equivalent epilogs are shared or otherwise no longer duplicated, with the generated code becoming smaller.

Following example generates two identical function epilogs. I would expect some overall size improvements from only having a single epilog and jumping to it. https://godbolt.org/z/Mch1hGKfx

static bool TwoEpilogs(in Matrix4x4 a, in Matrix4x4 b)
{
    var c = a * b;

    if (c[0, 0] == 1.0f && c[1, 1] == 1.0f)
    {
        return true;
    }

    return false;
}

G_M43597_IG05 and G_M43597_IG07 are the same

; Method Program.EntryPoint:TwoEpilogs(byref,byref):ubyte (FullOpts)
G_M43597_IG01:  ;; offset=0x0000
       sub      rsp, 152
       vmovaps  xmmword ptr [rsp+0x80], xmm6
       vmovaps  xmmword ptr [rsp+0x70], xmm7
       vmovaps  xmmword ptr [rsp+0x60], xmm8
       vmovaps  xmmword ptr [rsp+0x50], xmm9
       vmovaps  xmmword ptr [rsp+0x40], xmm10
       vxorps   xmm4, xmm4, xmm4
       vmovdqu  ymmword ptr [rsp], ymm4
       vmovdqu  ymmword ptr [rsp+0x20], ymm4
						;; size=55 bbWeight=1 PerfScore 14.58

G_M43597_IG02:  ;; offset=0x0037
       ; bunch of multiplication code
       vucomiss xmm0, dword ptr [reloc @RWD00]
       jp       SHORT G_M43597_IG04
       jne      SHORT G_M43597_IG04
						;; size=302 bbWeight=1 PerfScore 122.00

G_M43597_IG03:  ;; offset=0x0165
       vmovss   xmm0, dword ptr [rsp+0x14]
       vucomiss xmm0, dword ptr [reloc @RWD00]
       jp       SHORT G_M43597_IG04
       je       SHORT G_M43597_IG06
						;; size=18 bbWeight=0.50 PerfScore 4.50

G_M43597_IG04:  ;; offset=0x0177
       xor      eax, eax
						;; size=2 bbWeight=0.50 PerfScore 0.12

G_M43597_IG05:  ;; offset=0x0179
       vmovaps  xmm6, xmmword ptr [rsp+0x80]
       vmovaps  xmm7, xmmword ptr [rsp+0x70]
       vmovaps  xmm8, xmmword ptr [rsp+0x60]
       vmovaps  xmm9, xmmword ptr [rsp+0x50]
       vmovaps  xmm10, xmmword ptr [rsp+0x40]
       add      rsp, 152
       ret      
						;; size=41 bbWeight=0.50 PerfScore 10.62

G_M43597_IG06:  ;; offset=0x01A2
       mov      eax, 1
						;; size=5 bbWeight=0.50 PerfScore 0.12

G_M43597_IG07:  ;; offset=0x01A7
       vmovaps  xmm6, xmmword ptr [rsp+0x80]
       vmovaps  xmm7, xmmword ptr [rsp+0x70]
       vmovaps  xmm8, xmmword ptr [rsp+0x60]
       vmovaps  xmm9, xmmword ptr [rsp+0x50]
       vmovaps  xmm10, xmmword ptr [rsp+0x40]
       add      rsp, 152
       ret      
						;; size=41 bbWeight=0.50 PerfScore 10.62
RWD00  	dd	3F800000h		;         1
; Total bytes of code: 464