diff -r e1ea5a6379c9 -r 4cd4c204578c src/HOL/HOL.thy
--- a/src/HOL/HOL.thy Thu May 07 15:34:28 2015 +0200
+++ b/src/HOL/HOL.thy Sat May 09 12:19:24 2015 +0200
@@ -1270,6 +1270,8 @@
lemma False_implies_equals: "(False \ P) \ Trueprop True"
by default simp_all
+(* This is not made a simp rule because it does not improve any proofs
+ but slows some AFP entries down by 5% (cpu time). May 2015 *)
lemma implies_False_swap: "NO_MATCH (Trueprop False) P \
(False \ PROP P \ PROP Q) \ (PROP P \ False \ PROP Q)"
by(rule swap_prems_eq)
@@ -1297,7 +1299,7 @@
lemmas [simp] =
triv_forall_equality (*prunes params*)
True_implies_equals implies_True_equals (*prune True in asms*)
- False_implies_equals implies_False_swap (*prune False in asms*)
+ False_implies_equals (*prune False in asms*)
if_True
if_False
if_cancel