re PR c++/91987 (-fstrict-eval-order issues)

re PR c++/91987 (-fstrict-eval-order issues)

	PR c++/91987
cp/
	* decl2.c (grok_array_decl): For -fstrong-eval-order, when array ref
	operands have been swapped and at least one operand has side-effects,
	revert the swapping before calling build_array_ref.
	* typeck.c (cp_build_array_ref): For non-ARRAY_TYPE array ref with
	side-effects on the index operand, if -fstrong-eval-order use
	save_expr around the array operand.
	(cp_build_binary_op): For shifts with side-effects in the second
	operand, wrap first operand into SAVE_EXPR and evaluate it before
	the shift.
	* semantics.c (handle_omp_array_sections_1): Temporarily disable
	flag_strong_eval_order during OMP_CLAUSE_REDUCTION array section
	processing.
	* cp-gimplify.c (gimplify_to_rvalue): New function.
	(cp_gimplify_expr): Use it.
testsuite/
	* g++.dg/cpp1z/eval-order6.C: New test.
	* g++.dg/cpp1z/eval-order7.C: New test.
	* g++.dg/cpp1z/eval-order8.C: New test.
	* c-c++-common/gomp/pr91987.c: New test.

From-SVN: r276860