Bugfix for shift count limits

32-bit shifts in OCaml must have a shift count < 32, not <= 32.
stedolan · Sep 23, 2022 · dbffd75 · dbffd75
1 parent 69ec075
commit dbffd75
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Showing 3 changed files with 5 additions and 5 deletions.
diff --git a/dune-workspace.all b/dune-workspace.all
@@ -26,4 +26,5 @@
 (context (opam (switch 4.13.1) ))
 (context (opam (switch 4.13.1+flambda)))
 (context (opam (switch 4.14.0) ))
+(context (opam (switch 4.14.0+32bit) ))
 (context (opam (switch 4.14.0+flambda)))
diff --git a/src/malfunction_interpreter.ml b/src/malfunction_interpreter.ml
@@ -145,7 +145,7 @@ let rec interpret locals env : t -> value = function
           | `Bigint -> ()
           | (`Int|`Int32|`Int64) as ty ->
              let w = bitwidth ty in
-             if c < 0 || c > w then
+             if c < 0 || c >= w then
                fail "invalid shift count %d" c in
         truncate ty Z.(match op with
         | `Lsl -> shift_left n c

diff --git a/test/shifts.test b/test/shifts.test
@@ -24,8 +24,7 @@
 (test-undefined (>> 1 113455345))
 (test-undefined (a>> 1 113455345))
 
-(test (<<.i32 1.i32 32) 0.i32)
-(test-undefined (<<.i32 1.i32 33))
+(test (<<.i32 1.i32 31) -2147483648.i32)
+(test-undefined (<<.i32 1.i32 32))
 (test (>>.i32 (neg.i32 1.i32) 31) 1.i32)
-(test (>>.i32 (neg.i32 1.i32) 32) 0.i32)
-(test-undefined (>>.i32 (neg.i32 1.i32) 33))
+(test-undefined (>>.i32 (neg.i32 1.i32) 32))