[RISCV] Convert more constant splats in tests to splat shorthand. NFC

[lukel97]

A handy shorthand for specifying the shufflevector(insertelement(poison, foo, 0), poison, zeroinitializer) splat pattern was introduced in #74620.

Some of the RISC-V tests were converted over to use this new form in dbb65dd, this patch handles the rest which didn't have any codegen diffs.

This not only converts some constant expressions to the new form, but also instruction sequences that weren't previously constant expressions to constant expressions as well. In some cases this affects codegen, but these have been omitted here and will be handled in a separate PR to show the diff better.

Script used for reference

#!/usr/bin/perl
use warnings;
use strict;

open my $fh, '<', $ARGV[0] or die $!;
my $data = do { local $/; <$fh> };

$data =~ s/shufflevector\s*\(<.+>\s*insertelement\s*\(<.+>\s*(?:poison|undef),\s+(.+),\s+i\d+\s0\),\s+<.+>\s+(?:poison|undef),\s<.+>\s+zeroinitializer\)/splat ($1)/g;

my @funcs = split('(define)', $data);

foreach my $func (@funcs) {
    while ($func =~ /\n\s+%([\w\.]+)\s=\sinsertelement\s<.+x\s(\w+)>\s(?:poison|undef),\s\2\s([\.\-\w]+),\si\d+\s0\n\s+%([\w\.]+)\s=\sshufflevector\s<.+>\s%\1,\s<.+>\s(?:poison|undef),\s<.+>\szeroinitializer/g) {
	my $type = $2;
	my $val = $3;
	my $splat_var = $4;

	$func =~ s/\n\s+%([\w\.]+)\s=\sinsertelement\s<.+x\s(\w+)>\s(?:poison|undef),\s\2\s([\.\-\w]+),\si\d+\s0\n\s+%([\w\.]+)\s=\sshufflevector\s<.+>\s%\1,\s<.+>\s(?:poison|undef),\s<.+>\szeroinitializer//;

	$func =~ s/%$splat_var/splat ($type $val)/g;
    }
}

open my $out, '>', $ARGV[0] or die $!;

print $out @funcs;

[wangpc-pp]

LGTM, thanks!
(Did you convert these tests manually or via some scripts?)

[lukel97]

LGTM, thanks!

(Did you convert these tests manually or via some scripts?)

I wrote a Perl script, it should be attached it in the PR description. I really don't know Perl at all though, I'm sure it's terrible!

[wangpc-pp]

LGTM, thanks!
(Did you convert these tests manually or via some scripts?)

I wrote a Perl script, it should be attached it in the PR description. I really don't know Perl at all though, I'm sure it's terrible!

Yeah, I see it now (the script is collapsed so I didn't notice it).

[topperc]

LGTM assuming no codegen changes are hidden in here. I see you split those out.