mips64-linux-gnuabi64 testsuite breakage

[Maciej W. Rozycki]

On Wed, 26 Apr 2023, YunQiang Su wrote:

> > Since 32f1c80375e "MIPS: support mips*64 as CPU and gnuabi64 as ABI",
> 
> I will fix the test suite.
> The reason is that: the previous test suite assumes the default ABI is
> n32 even the triple
> with -gnuabi64.

 I can see extra 3346 regressions across various MIPS targets compared to 
a checkout from Jan.  Including ones like (parts of log trimmed for 
clarity):

../as-new  --defsym count=960 /scratch/vol1/binutils/binutils-mips-test/binutils-src/gas/testsuite/gas/mips/branch-swap-2.s
gas/testsuite/gas/mips/branch-swap-2.s:1: Fatal error: `micromips' cannot be used with `mips32r6'
FAIL: MIPS branch swapping (960)

for `mips-img-elf' which indicates that the default architecture has 
changed for GAS for this target.  I think this is due to your commit 
9171de358f23 ("MIPS: default output r6 obj if the triple is r6"), which 
has this part among others:

+	# If Vendor is IMG, then MIPSr6 is used
+	case ${target} in
+	  mips*64*-img-*)
+	    mips_cpu=mips64r6
+	    ;;
+	  mips*-img-*)
+	    mips_cpu=mips32r6
+	    ;;
+	esac

Not only this change is wrong (you can't just arbitrarily change a 
configuration that has been in the wild for ~8.5 years as it'll break 
things for people who rely on the established semantics), but it hasn't 
been properly verified either, as a change is supposed not to cause 
regressions in the testsuite.

 Please revert the part quoted and fix the regressions.  Thank you.

  Maciej