`@shrExact` omits runtime safety check for compile-time-known RHS vector operand

[amp-59]

Zig Version

0.13.0-dev.211+6a65561e3

Steps to Reproduce and Observed Behaviour

Compile and run example program with zig run shr_vec_ov_comptime_rhs.zig
shr_vec_ov_comptime_rhs.zig:

pub fn main() void {
 var v: @Vector(4, u32) = @splat(1);

 const pc_before: u16 = @reduce(.Add, @popCount(v));

 v = @shrExact(v, @splat(1));

 const pc_after: u16 = @reduce(.Add, @popCount(v));

 if (pc_after != pc_before) {
 unreachable;
 }
}

Output:

zig run shr_vec_ov_comptime_rhs.zig
thread 9474 panic: reached unreachable code
~/.local/share/test/shr_vec_ov_comptime_rhs.zig:11:9: 0x10344c5 in main (shr_vec_ov_comptime_rhs)
 unreachable;
 ^
~/.local/src/zig-linux-x86_64-0.13.0-dev.211+6a65561e3/lib/std/start.zig:514:22: 0x1033c19 in posixCallMainAndExit (shr_vec_ov_comptime_rhs)
 root.main();
 ^
~/.local/src/zig-linux-x86_64-0.13.0-dev.211+6a65561e3/lib/std/start.zig:266:5: 0x1033781 in _start (shr_vec_ov_comptime_rhs)
 asm volatile (switch (native_arch) {
 ^
???:?:?: 0x0 in ??? (???)

Expected Behaviour

Compile and run example program with zig run shr_vec_ov_runtime_rhs.zig
shr_vec_ov_runtime_rhs.zig:

var rhs: @Vector(4, u5) = @splat(1);

pub fn main() void {
 var v: @Vector(4, u32) = @splat(1);

 const pc_before: u16 = @reduce(.Add, @popCount(v));

 v = @shrExact(v, rhs);

 const pc_after: u16 = @reduce(.Add, @popCount(v));

 if (pc_after != pc_before) {
 unreachable;
 }
}

Output:

zig run shr_vec_ov_runtime_rhs.zig
thread 9946 panic: right shift overflowed bits
~/.local/share/test/shr_vec_ov_runtime_rhs.zig:8:5: 0x10344ea in main (shr_vec_ov_runtime_rhs)
 v = @shrExact(v, rhs);
 ^
~/.local/src/zig-linux-x86_64-0.13.0-dev.211+6a65561e3/lib/std/start.zig:514:22: 0x1033c19 in posixCallMainAndExit (shr_vec_ov_runtime_rhs)
 root.main();
 ^
~/.local/src/zig-linux-x86_64-0.13.0-dev.211+6a65561e3/lib/std/start.zig:266:5: 0x1033781 in _start (shr_vec_ov_runtime_rhs)
 asm volatile (switch (native_arch) {
 ^
???:?:?: 0x0 in ??? (???)

The only difference between the two examples is that the shift amount in the latter example is runtime-known. The outcomes should be the same.