phiprop: Small compile time improvement for phiprop

Now that post dom information is only needed when the new store
can trap (since r16-5555-g952e145796d), only calculate it when
that is the case. It was calculated on demand by
r14-2051-g3124bfb14c0bdc. This just changes when we need to
calculate it.

Pushed as obvious.

gcc/ChangeLog:

	* tree-ssa-phiprop.cc (propagate_with_phi): Only
	calculate on demand post dom info when the new store
	might trap.

Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>

diff --git a/gcc/tree-ssa-phiprop.cc b/gcc/tree-ssa-phiprop.cc
index 04aa138f521c2f9416a1a091916ddc5e2bade2ac..0c840b182e02d411e45094905d4e270bb00fc03b 100644 (file)
--- a/gcc/tree-ssa-phiprop.cc
+++ b/gcc/tree-ssa-phiprop.cc
@@ -339,7 +339,8 @@ propagate_with_phi (basic_block bb, gphi *vphi, gphi *phi,
       tree vuse;
       bool delay = false;
 
-      if (!dom_info_available_p (cfun, CDI_POST_DOMINATORS))
+      if (canpossible_trap
+         && !dom_info_available_p (cfun, CDI_POST_DOMINATORS))
        calculate_dominance_info (CDI_POST_DOMINATORS);
 
       /* Only replace loads in blocks that post-dominate the PHI node.  That