[Bug tree-optimization/95185] Failure to optimize specific kind of sign comparison check

[arjun.is at lostca dot se via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95185

Arjun Shankar  changed:

   What|Removed |Added

 CC||arjun.is at lostca dot se

--- Comment #3 from Arjun Shankar  ---
If the code is compiled as C, gcc produces essentially the same code as clang
with some differences in the schedule of instructions:
https://godbolt.org/z/8nsq16Pen

It's when the code is compiled as C++ that gcc does worse:
https://godbolt.org/z/dK8hTEhjr

The difference lies in the front-ends. The C front-end already appears to know
that this is a XOR. testcase.c.004t.original looks like:

  return (int) (x < 0 ^ y <= 0);

On the other hand, g++ outputs:

  return  = x >= 0 == y <= 0;

[Bug middle-end/19987] [meta-bug] fold missing optimizations in general

[arjun.is at lostca dot se via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19987
Bug 19987 depends on bug 95176, which changed state.

Bug 95176 Summary: Failure to optimize division followed by multiplication to 
modulo followed by subtraction
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |FIXED

[Bug tree-optimization/95176] Failure to optimize division followed by multiplication to modulo followed by subtraction

[arjun.is at lostca dot se via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

Arjun Shankar  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
   Target Milestone|--- |12.0
 Resolution|--- |FIXED

--- Comment #3 from Arjun Shankar  ---
This should make it to GCC 12 when it's released, so I'm closing it
accordingly.

[Bug tree-optimization/97223] Failure to optimize comparison of char arithmetic to single comparison

[arjun.is at lostca dot se via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97223

Arjun Shankar  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
   Target Milestone|--- |11.0
 Resolution|--- |FIXED
 CC||arjun.is at lostca dot se

--- Comment #5 from Arjun Shankar  ---
Looks like this was fixed by the time GCC 11 was released. I'm closing this bug
out.

[Bug tree-optimization/95176] Failure to optimize division followed by multiplication to modulo followed by subtraction

[arjun.is at lostca dot se via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

Arjun Shankar  changed:

   What|Removed |Added

 CC||arjun.is at lostca dot se

--- Comment #2 from Arjun Shankar  ---
This appears to have been fixed as bug 96696 via the following commit:

https://gcc.gnu.org/g:3dcd1334b4f522352b80814513fdca902fc2a207