[PATCH V5, 0/2] PR target/105325: Fix constraint issue with power10 fusion

[Michael Meissner <meissner@linux.ibm.com>]

I have posted 4 previous versions of this patch (April 26th, March 28th, March
24th, and March 21st).

In this patch, rather than just add changes to the existing code in
genfusion.pl, I rewrote the function completely.  There are two patches within
this patch set:

    * The first patch rewrites the perl function to be more readable.  This
      patch produces the same output for fusion.md that the current version
      generates.

    * The second patch then using the rewrite in the first patch adds the
      changes to fix the problem.

The issue with the original bug is the power10 load GPR + cmpi -1/0/1 fusion
optimization generates illegal assembler code when the -fstack-protector option
is used.

Ultimately the code was dying because the fusion load + compare -1/0/1 patterns
did not handle the possibility that the load might be prefixed.

The main cause is the constraints for the individual loads in the fusion did not
match the machine.  In particular, LWA is a ds format instruction when it is
unprefixed.  The code did not also set the prefixed attribute correctly.

These patch hav been tested on:

    * Little endian power9 with both IEEE and IBM long double
    * Little endian power10
    * Big endian power8 using both 32-bit and 64-bit code generation.

Can I check these into the master branch?  Assuming I can check this in, I will
also commit to the active GCC branches after a burn-in period.

-- 
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: meissner@linux.ibm.com