Fix compilation of catches with multiple handlers

Changes

@@ -8,6 +8,9 @@ Working version
 - GPR#1579: Add a separate types for clambda primitives
   (Pierre Chambart, review by Vincent Laviron and Mark Shinwell)
 
+- GPR#1973: fix compilation of catches with multiple handlers
+  (Vincent Laviron)
+
 - GPR#2228: refactoring the handling of .cmi files by moving it from
   Env to a new module Persistent_env
   (Gabriel Scherer, review by Jérémie Dimino and Thomas Refis)

asmcomp/linearize.ml

@@ -272,7 +272,8 @@ let rec linear i n =
       let n2 = List.fold_left2 (fun n (_nfail, handler) lbl_handler ->
           match handler.Mach.desc with
           | Iend -> n
-          | _ -> cons_instr (Llabel lbl_handler) (linear handler n))
+          | _ -> cons_instr (Llabel lbl_handler)
+                   (linear handler (add_branch lbl_end n)))
           n1 handlers labels_at_entry_to_handlers
       in
       let n3 = linear body (add_branch lbl_end n2) in

testsuite/tests/asmgen/catch-multiple.cmm

@@ -0,0 +1,20 @@
+(* TEST
+files = "main.c"
+arguments = "-DINT_INT -DFUN=catch_multiple main.c"
+* asmgen
+*)
+
+(*
+Expected output:
+catch_multiple(0) == -1
+catch_multiple(1) == 1
+*)
+
+(function "catch_multiple" (b:int)
+  (let x
+    (catch
+      (if (== b 0) (exit zero)
+          (exit other))
+     with (zero) -1
+     and (other) ( * b b))
+    x))

testsuite/tests/asmgen/ocamltests

@@ -2,6 +2,7 @@ arith.cmm
 catch-rec.cmm
 catch-try.cmm
 catch-float.cmm
+catch-multiple.cmm
 catch-try-float.cmm
 checkbound.cmm
 even-odd-spill.cmm