gimple: Canonical order for invariants [PR118902]

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.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>

0 files changed, 0 insertions, 0 deletions