Re: [PATCH] Fix PR30028, fold sin, cos to sincos on the tree-level

[Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>]

> 	* tree-ssa-math-opts.c (execute_cse_reciprocals_1): Gate
> 	with !optimize_size && flag_unsafe_math_optimizations.
> 	(gate_cse_reciprocals): Only gate with optimize.
> 	(execute_cse_sincos_1): New routine to CSE sin and cos to sincos.
> 	(execute_cse_reciprocals): Call it.

If you don't want to walk the whole tree once more, please rename this 
function.

> +   /* Simply insert cexpi at the argument definition site.  */

No way :-(

Something like this caused an enormous regression on povray (it's in 
bugzilla, I don't remember the number though).  That's the reason why 
tree-ssa-math-opts.c had to be rewritten to do the dominator magic it does.

Paolo