fix: fixes -O2 optimizer

Do not move pop XX instructions up when the are after an
LD SP, NN

Author: boriel

src/arch/z80/peephole/opts/028_o2_pop_up.opt

@@ -18,7 +18,8 @@ REPLACE {{
 }}
 
 IF {{
-  !(INSTR($2) IN (jp, jr, ret, call, djnz, rst)) && !NEEDS($2, (sp, $1)) && !IS_LABEL($2)
+  !(INSTR($2) IN (jp, jr, ret, call, djnz, rst)) && !NEEDS($2, (sp, $1)) && !IS_LABEL($2) &&
+  OP1($2) <> "sp" && OP2($2) <> "sp"
 }}
 
 WITH {{

tests/functional/zxnext/opt2_epilogue.asm

@@ -0,0 +1,31 @@
+	org 32768
+.core.__START_PROGRAM:
+	di
+	push iy
+	ld iy, 0x5C3A  ; ZX Spectrum ROM variables address
+	ld hl, 0
+	add hl, sp
+	ld (.core.__CALL_BACK__), hl
+	ei
+	jp .core.__MAIN_PROGRAM__
+.core.__CALL_BACK__:
+	DEFW 0
+.core.ZXBASIC_USER_DATA:
+	; Defines USER DATA Length in bytes
+.core.ZXBASIC_USER_DATA_LEN EQU .core.ZXBASIC_USER_DATA_END - .core.ZXBASIC_USER_DATA
+	.core.__LABEL__.ZXBASIC_USER_DATA_LEN EQU .core.ZXBASIC_USER_DATA_LEN
+	.core.__LABEL__.ZXBASIC_USER_DATA EQU .core.ZXBASIC_USER_DATA
+.core.ZXBASIC_USER_DATA_END:
+.core.__MAIN_PROGRAM__:
+	ld hl, 0
+	ld b, h
+	ld c, l
+.core.__END_PROGRAM:
+	di
+	ld hl, (.core.__CALL_BACK__)
+	ld sp, hl
+	pop iy
+	ei
+	ret
+	;; --- end of user code ---
+	END

tests/functional/zxnext/opt2_epilogue.bas

@@ -0,0 +1,2 @@
+REM Test empty program for prologue and epilogue
+REM for ZX Next using O2 optimizer