Fuzzer failure in fuzz_bounds

[steven-johnson]

testcase-4722946583101440.zip

Running fuzz_bounds on the enclosed file produces a failure (note that this test emits the scope dump for failures):

$ ./build/linux-x64-fuzzer/test/fuzz/fuzz_bounds testcase-4722946583101440
can't prove upper bound: (0 <= -2147483648)
a = (uint16)0
b = (uint16)0
c = (uint16)0
d = (uint16)0
e = (uint16)0
select(int32((uint16)c) >= int32((uint16)c), int32x2(ramp(uint32((uint16)a), (uint32)2147483648, 2)), x2(-128))
[0, -2147483648]
In vector lane 0:
int32((uint16)a) -> 0
scope {
	a : [(uint16)0, (uint16)0]
	b : [(uint16)0, (uint16)0]
	c : [(uint16)0, (uint16)0]
	d : [(uint16)0, (uint16)0]
	e : [(uint16)0, (uint16)0]
}

[steven-johnson]

Initially assigning to @abadams for triage

[abadams]

I think this is the issue in #7807