On 10/24/23 04:50, Richard Sandiford wrote:
The exit block can have multiple predecessors, for example if the
function calls __builtin_eh_return. We might then need PHI nodes
for values that are live on exit.
RTL-SSA uses the normal dominance frontiers approach for calculating
where PHI nodes are needed. However, dominannce.cc only calculates
dominators for normal blocks, not the exit block.
calculate_dominance_frontiers likewise only calculates dominance
frontiers for normal blocks.
This patch fills in the “missing” frontiers manually.
gcc/
* rtl-ssa/internals.h (build_info::exit_block_dominator): New
member variable.
* rtl-ssa/blocks.cc (build_info::build_info): Initialize it.
(bb_walker::bb_walker): Use it, moving the computation of the
dominator to...
(function_info::process_all_blocks): ...here.
(function_info::place_phis): Add dominance frontiers for the
exit block.
OK
jeff
