* fold-const.c (const_binop): Avoid performing the FP operation at
compile-time, if either operand is NaN and we honor signaling NaNs,
or if we're dividing by zero and either flag_trapping_math is set
or the desired mode doesn't support infinities.
(fold_initializer): New function to fold an expression ignoring any
potential run-time exceptions or traps.
* tree.h (fold_initializer): Prototype here.
* c-typeck.c (build_binary_op): Move to the end of the file so
that intializer_stack is in scope. If constructing an initializer,
i.e. when initializer_stack is not NULL, use fold_initializer to
fold expressions.
* simplify-rtx.c (simplify_binary_operation): Likewise, avoid
performing FP operations at compile-time, if they would raise an
exception at run-time.
From-SVN: r69533
