Ditch stack_check instruction

cranelift/docs/langref.rst

@@ -546,8 +546,6 @@ instructions before instruction selection::
 When Cretonne code is running in a sandbox, it can also be necessary to include
 stack overflow checks in the prologue.
 
-.. autoinst:: stack_check
-
 Global variables
 ----------------
 

cranelift/filetests/isa/x86/legalize-memory.cton

@@ -108,17 +108,3 @@ ebb0(v0: i32, v999: i64):
     ; nextln: v2 = load.f32 v1+0x7fff_ffff
     return v2
 }
-
-; Stack overflow check.
-; The stack limit is stored in a pointer-sized global variable.
-function %stkchk(i64 vmctx) baldrdash {
-    gv0 = vmctx+64
-
-ebb0(v0: i64):
-    ; check: ebb0(
-    stack_check gv0
-    ; check: $(limit=$V) = load.i64 notrap aligned
-    ; check: $(flags=$V) = ifcmp_sp $limit
-    ; check: trapif uge $flags, stk_ovf
-    return
-}