[Bug rtl-optimization/90496] New: ICE in RTL pass pro_and_epilogue when all of `-flto -fsanitize=address -fstack-usage` are used on trivial source

[gcc_bugs at codyps dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90496

Bug ID: 90496
   Summary: ICE in RTL pass pro_and_epilogue when all of `-flto
-fsanitize=address -fstack-usage` are used on trivial
source
   Product: gcc
   Version: 8.3.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: rtl-optimization
  Assignee: unassigned at gcc dot gnu.org
  Reporter: gcc_bugs at codyps dot com
  Target Milestone: ---

Compiling `int main(void) { return 0; }` with _all_ of `-flto -fsantize=address
-fstack-usage` results in an ICE:

```
$ cat test1.c 
int main(void)
{
return 0;
}
$ ./test
+ : gcc
+ gcc -v
Using built-in specs.
COLLECT_GCC=/bin/gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
--enable-cet=auto
Thread model: posix
gcc version 8.3.0 (GCC) 
+ gcc -o test1_a test1.c -flto -fsanitize=address
+ gcc -o test1_b test1.c -flto -fstack-usage
+ gcc -o test1_c test1.c -fsanitize=address -fstack-usage
+ gcc -o test1_d test1.c -flto -fsanitize=address -fstack-usage
during RTL pass: pro_and_epilogue
In function ‘_GLOBAL__sub_I_00099_0_cc3AMKZf.ltrans0.o’:
lto1: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.archlinux.org/> for instructions.
lto-wrapper: fatal error: /bin/gcc returned 1 exit status
compilation terminated.
/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status

```

Script from above:
```
#! /bin/bash
set -xeuf -o pipefail
: ${CC:=gcc}
$CC -v
$CC -o test1_a test1.c -flto -fsanitize=address
$CC -o test1_b test1.c -flto -fstack-usage
$CC -o test1_c test1.c -fsanitize=address -fstack-usage
$CC -o test1_d test1.c -flto -fsanitize=address -fstack-usage
```

[Bug driver/90983] New: manual documents `-Wno-stack-usage` flag, but it is unrecognized

[gcc_bugs at codyps dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90983

Bug ID: 90983
   Summary: manual documents `-Wno-stack-usage` flag, but it is
unrecognized
   Product: gcc
   Version: 9.1.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: driver
  Assignee: unassigned at gcc dot gnu.org
  Reporter: gcc_bugs at codyps dot com
  Target Milestone: ---

Previously (in gcc-8 of some version), `-Wstack-usage=0` would disable
stack-usage checking. In 9.1.0, however, `-Wstack-usage=0` appears to read
"warn if any usage greater than 0 bytes occurs". This lead me to try to use the
`-Wno-stack-usage` flag, which is documented in the manual:

 -Wno-stack-usage
   Disable -Wstack-usage= warnings.  The option is equivalent to
-Wstack-usage=SIZE_MAX or larger.

However, this negative flag appears non-functional:

[cody@franklin gcc]$ echo 'int main(void) { return 0; }' | /usr/bin/gcc -Wall
-Werror -Wextra -Wstack-usage=0 -Wno-stack-usage -c -x c -
: In function ‘main’:
:1:5: error: stack usage is 16 bytes [-Werror=stack-usage=]
: At top level:
cc1: error: unrecognized command line option ‘-Wno-stack-usage’ [-Werror]
cc1: all warnings being treated as errors


(Note: I've used `-Wstack-usage=0` here to generate show that
`-Wno-stack-usage` fails to disable the stack-usage warning. If no warning
other warning is generated, the unrecognized command line option of
`-Wno-stack-usage` is not emitted, even with `-Werror`).

Indeed, looking at `gcc/common.opt` shows `RejectNegative` for `Wstack-usage=`.

I haven't yet located where the behavior of `Wstack-usage` was changed wrt `0`.

[Bug driver/90983] manual documents `-Wno-stack-usage` flag, but it is unrecognized

[gcc_bugs at codyps dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90983

--- Comment #1 from Cody Schafer  ---
It appears that 

commit 8e18705e1fb8213834b09c91c3ed7b15c8540d59
Author: msebor 
Date:   Fri Jul 20 20:51:20 2018 +

PR middle-end/82063 - issues with arguments enabled by -Wall

Might be the change in `-Wstack-usage=0` behavior. Seems likely that this also
affects `-Wframe-larger-that=` and `-Wlarger-than=` as they received similar
`gcc/common.opt` modifications.

This also introduced the documentation for `-Wno-stack-usage`.