On Fri, 7 Feb 2014, Jan Hubicka wrote: > > On Thu, 6 Feb 2014, Jan Hubicka wrote: > > > > > Hi, > > > at WPA we currently read trees accessed by jump functions and then copy > > > them > > > to remove location that is already known to be UNKNOWN and then keep > > > copying > > > them for every inline clone introduced (and there are many for firefox) > > > > > > This patch makes us to copy only when expression really has an location > > > in it. > > > > > > Bootstrapped/regtested x86_64-linux, OK? > > > > Hmm, I think you either can use just > > > > if (EXPR_P (expr)) > > walk_tree (&expr, prune_expr_location, NULL, NULL); > > > > or you miss unsharing and create invalid shared trees when > > the expr does not contain locations. > > > > I fear it's the latter, given how ipa_set_jf_* is used. > > Well, ipa-prop analysis takes random operands from GIMPLE bodies and > stores them into jump function. Then it streams in/out, propagates and > eventually uses them as a replacements for bodies. > > We use unshare_without_location primarily to prevent LTO from need to stream > stale BLOCK expressions and to avoid inserting wrong blocks into clones > http://gcc.gnu.org/ml/gcc-patches/2012-12/msg01176.html > http://gcc.gnu.org/ml/gcc-patches/2012-09/msg01343.html
I know. > Calling prine_expr_location would kill locations in the original > function body they are taken from. For constant JF, they are IP Ah, true. > invariants, so I do not think they need unsharing. THe arithmetic is > never inserted back to GIMPLE code. Well. Our sharing indeed allows is_gimple_min_invariant nodes to be shared (tree-cfg.c:tree_node_can_be_shared). So your original patch looks ok. Thanks, Richard. > I can also just add no_unshare parameter to jump functions to avoid the > unsharing during stream-in, possibly.
