From 11db3838a8cbfd09ecca368e87305054832a4719 Mon Sep 17 00:00:00 2001
From: xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e>
Date: Sun, 23 Feb 2014 08:23:10 +0000
Subject: 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
---
 backend/Regalloc.ml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'backend/Regalloc.ml')

diff --git a/backend/Regalloc.ml b/backend/Regalloc.ml
index b21eeb0a..b736f291 100644
--- a/backend/Regalloc.ml
+++ b/backend/Regalloc.ml
@@ -228,7 +228,7 @@ let vset_addros vos after =
 let live_before instr after =
   match instr with
   | Xmove(src, dst) | Xspill(src, dst) | Xreload(src, dst) ->
-      if VSet.mem dst after
+      if VSet.mem dst after || is_stack_reg src
       then VSet.add src (VSet.remove dst after)
       else after
   | Xparmove(srcs, dsts, itmp, ftmp) ->
@@ -302,7 +302,7 @@ let rec dce_parmove srcs dsts after =
   | [], [] -> [], []
   | src1 :: srcs, dst1 :: dsts ->
       let (srcs', dsts') = dce_parmove srcs dsts after in
-      if VSet.mem dst1 after
+      if VSet.mem dst1 after || is_stack_reg src1
       then (src1 :: srcs', dst1 :: dsts')
       else (srcs', dsts')
   | _, _ -> assert false
@@ -310,7 +310,7 @@ let rec dce_parmove srcs dsts after =
 let dce_instr instr after k =
   match instr with
   | Xmove(src, dst) ->
-      if VSet.mem dst after
+      if VSet.mem dst after || is_stack_reg src
       then instr :: k
       else k
   | Xparmove(srcs, dsts, itmp, ftmp) ->
-- 
cgit