On 4/17/25 11:35 AM, Andrew Pinski wrote:
So unlike constants, address invariants are currently put first if
used with a SSA NAME.
It would be better if address invariants are consistent with constants
and this patch changes that.
gcc.dg/tree-ssa/pr118902-1.c is an example where this canonicalization
can help. In it if `p` variable was a global variable, FRE (VN) would have
figured
it out that `a` could never be equal to `&p` inside the loop. But without the
canonicalization we end up with `&p == a.0_1` which VN does try to handle for
conditional
VN.
Bootstrapped and tested on x86_64.
PR tree-optimization/118902
gcc/ChangeLog:
* fold-const.cc (tree_swap_operands_p): Place invariants in the first
operand
if not used with constants.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/pr118902-1.c: New test.
OK
jeff
