re PR rtl-optimization/576 (gcc performs invalid optimization with float operations when different rounding mode.)
PR rtl-optimization/576
* real.c (real_arithmetic): Change return type from void to bool
to return an indication that the result may be inexact.
* real.h (real_arithmeric): Update prototype.
* fold-const.c (const_binop): Don't constant fold floating
point expressions when the user specifies -frounding-math and
the result may depend upon the run-time rounding mode.
(fold_convert_const_real_from_real): Clean-up.
(fold_initializer): Ignore flag_rounding_math for initializers.
* simplify-rtx.c (simplify_binary_operation): Likewise, don't
constant fold FP operations with flag_rounding_math if the
result may depend upon the run-time rounding mode.
From-SVN: r94020
