Completely unnecessary compiler warnings In function ‘dasm_setupglobal’

[VARGA-Peter]

### Description

/bin/sh /builds/php-8.2.4/libtool --silent --preserve-dup-deps --tag CC --mode=compile gcc-12 -Iext/opcache/ -I/builds/php-8.2.4/ext/opcache/ -I/builds/php-8.2.4/include -I/builds/php-8.2.4/main -I/builds/php-8.2.4 -I/builds/php-8.2.4/ext/date/lib -I/usr/include/libxml2
-I/usr/include/libpng16 -I/builds/php-8.2.4/ext/mbstring/libmbfl -I/builds/php-8.2.4/ext/mbstring/libmbfl/mbfl -I/builds/php-8.2.4/TSRM -I/builds/php-8.2.4/Zend  -D_GNU_SOURCE -D_REENTRANT -pthread  -fno-common -Wformat-truncation -Wlogical-op -Wduplicated-cond -Wno-clobbered -Wall -Wextra -Wno-strict-aliasing -Wno-unused-parameter -Wno-sign-compare -g -O2 -fvisibility=hidden -pthread -Wimplicit-fallthrough=1 -DZTS -DZEND_SIGNALS    -Wno-implicit-fallthrough -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1 -DZEND_COMPILE_DL_EXT=1 -c /builds/php-8.2.4/ext/opcache/jit/zend_jit.c -o ext/opcache/jit/zend_jit.lo  -MMD -MF ext/opcache/jit/zend_jit.dep -MT ext/opcache/jit/zend_jit.lo
In file included from /builds/php-8.2.4/ext/opcache/jit/zend_jit.c:710:
In function ‘dasm_setupglobal’,
    inlined from ‘zend_jit_trace_allocate_exit_group’ at ext/opcache/jit/zend_jit_trace.c:95:2,
    inlined from ‘zend_jit_trace_allocate_exit_point’ at ext/opcache/jit/zend_jit_trace.c:125:11:
/builds/php-8.2.4/ext/opcache/jit/dynasm/dasm_x86.h:127:19: warning: array subscript -10 is outside array bounds of ‘void *[38]’ [-Warray-bounds]
  127 |   D->globals = gl - 10;  /* Negative bias to compensate for locals. */
      |                ~~~^~~~
In file included from /builds/php-8.2.4/ext/opcache/jit/zend_jit.c:768:
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc: In function ‘zend_jit_trace_allocate_exit_point’:
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc:143:14: note: at offset -80 into object ‘dasm_labels’ of size 304
  143 | static void* dasm_labels[zend_lb_MAX];
      |              ^~~~~~~~~~~
In function ‘dasm_setupglobal’,
    inlined from ‘zend_jit’ at /builds/php-8.2.4/ext/opcache/jit/zend_jit.c:2729:2:
/builds/php-8.2.4/ext/opcache/jit/dynasm/dasm_x86.h:127:19: warning: array subscript -10 is outside array bounds of ‘void *[38]’ [-Warray-bounds]
  127 |   D->globals = gl - 10;  /* Negative bias to compensate for locals. */
      |                ~~~^~~~
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc: In function ‘zend_jit’:
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc:143:14: note: at offset -80 into object ‘dasm_labels’ of size 304
  143 | static void* dasm_labels[zend_lb_MAX];
      |              ^~~~~~~~~~~
In function ‘dasm_setupglobal’,
    inlined from ‘zend_jit_trace’ at ext/opcache/jit/zend_jit_trace.c:4054:2:
/builds/php-8.2.4/ext/opcache/jit/dynasm/dasm_x86.h:127:19: warning: array subscript -10 is outside array bounds of ‘void *[38]’ [-Warray-bounds]
  127 |   D->globals = gl - 10;  /* Negative bias to compensate for locals. */
      |                ~~~^~~~
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc: In function ‘zend_jit_trace’:
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc:143:14: note: at offset -80 into object ‘dasm_labels’ of size 304
  143 | static void* dasm_labels[zend_lb_MAX];
      |              ^~~~~~~~~~~
In file included from /builds/php-8.2.4/ext/opcache/jit/zend_jit.c:4428:
ext/opcache/jit/zend_jit_trace.c:6472:86: warning: ‘gen_handler’ may be used uninitialized [-Wmaybe-uninitialized]
 6472 |                                                                         (gen_handler || !ra || !ra[ssa_op->op1_def]));
      |                                                                                      ^~
ext/opcache/jit/zend_jit_trace.c:4298:30: note: ‘gen_handler’ was declared here
 4298 |                         bool gen_handler;
      |                              ^~~~~~~~~~~
In function ‘dasm_setupglobal’,
    inlined from ‘zend_jit_trace_exit_to_vm’ at ext/opcache/jit/zend_jit_trace.c:7001:2,
    inlined from ‘zend_jit_blacklist_trace_exit’ at ext/opcache/jit/zend_jit_trace.c:7721:14:
/builds/php-8.2.4/ext/opcache/jit/dynasm/dasm_x86.h:127:19: warning: array subscript -10 is outside array bounds of ‘void *[38]’ [-Warray-bounds]
  127 |   D->globals = gl - 10;  /* Negative bias to compensate for locals. */
      |                ~~~^~~~
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc: In function ‘zend_jit_blacklist_trace_exit’:
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc:143:14: note: at offset -80 into object ‘dasm_labels’ of size 304
  143 | static void* dasm_labels[zend_lb_MAX];
      |              ^~~~~~~~~~~
In function ‘dasm_setupglobal’,
    inlined from ‘zend_jit_make_stubs’ at /builds/php-8.2.4/ext/opcache/jit/zend_jit.c:4712:2,
    inlined from ‘zend_jit_startup’ at /builds/php-8.2.4/ext/opcache/jit/zend_jit.c:5001:9:
/builds/php-8.2.4/ext/opcache/jit/dynasm/dasm_x86.h:127:19: warning: array subscript -10 is outside array bounds of ‘void *[38]’ [-Warray-bounds]
  127 |   D->globals = gl - 10;  /* Negative bias to compensate for locals. */
      |                ~~~^~~~
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc: In function ‘zend_jit_startup’:
/builds/php-8.2.4/ext/opcache/jit/zend_jit_x86.dasc:143:14: note: at offset -80 into object ‘dasm_labels’ of size 304
  143 | static void* dasm_labels[zend_lb_MAX];
      |              ^~~~~~~~~~~ 

### PHP Version

PHP 8.2.4

### Operating System

SLES 15.4 gcc 12

[nielsdos]

At least the gen_handler case is a false positive: I analysed that one a while back here: #10206 (comment)
We could still fix it by just moving the assignment to gen_handler upwards, which will silence the warning.
As for the others, I'm fairly certain I saw something passing by recently stating they are false positives:
LuaJIT/LuaJIT#969 & LuaJIT/LuaJIT#970

[iluuu1994]

I already fixed this in master. Backporting it seems harmless.

[iluuu1994]

Yeah, I'd say let's keep this as it is. I checked PHP 8.1 and there are various compiler warnings. We don't want to keep backporting these things when they pop up. If there's something that can lead to actual issues, we'll backport it of course.