testsuite: Add test for r11-4123
r11-4123 came without a test but I happened upon a nice test case that
got fixed by that revision. So I think it'd be good to add it. The
ICE was:
phi-1.C: In constructor 'ElementManager::ElementManager()':
phi-1.C:28:1: error: missing definition
28 | ElementManager::ElementManager() : array_(makeArray()) {}
| ^~~~~~~~~~~~~~
for SSA_NAME: _12 in statement:
_10 = PHI <_12(3), _11(5)>
PHI argument
_12
for PHI node
_10 = PHI <_12(3), _11(5)>
during GIMPLE pass: fixup_cfg
phi-1.C:28:1: internal compiler error: verify_ssa failed
gcc/testsuite/ChangeLog:
* g++.dg/torture/phi-1.C: New test.