In Regalloc, dead code elimination, don't eliminate move operations

that pop the x87 FP stack (var <- FP0).  Otherwise, (void) f();
where f returns a float eventually produces a FP stack overflow.


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2416 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

1 files changed, 6 insertions, 0 deletions

diff --git a/backend/XTL.ml b/backend/XTL.ml
index 46c59b0..9cb8e0a 100644
--- a/backend/XTL.ml
+++ b/backend/XTL.ml
@@ -64,6 +64,12 @@ let vlocs ll = List.map vloc ll
 let vmreg mr = L(R mr)
 let vmregs mrl = List.map vmreg mrl
 
+(* Tests over variables *)
+
+let is_stack_reg = function
+  | L(R r) -> Machregs.is_stack_reg r
+  | _      -> false
+
 (* Sets of variables *)
 
 module VSet = Set.Make(struct type t = var let compare = compare end)