Add missing integer promotion to unary plus

src/frontc/cabs2cil.ml

@@ -4031,8 +4031,17 @@ and doExp (asconst: bool)   (* This expression is used as a constant *)
         else
           E.s (error "Unary ~ on a non-integral type")
 
-    | A.UNARY(A.PLUS, e) -> doExp asconst e what
-
+    | A.UNARY(A.PLUS, e) ->
+        let (se, e', t) = doExp asconst e (AExp None) in
+        if isIntegralType t then
+          let tres = integralPromotion t in
+          let e'' = makeCastT ~kind:IntegerPromotion ~e:e' ~oldt:t ~newt:tres in
+          finishExp se e'' tres
+        else
+          if isArithmeticType t then
+            finishExp se e' t
+          else
+            E.s (error "Unary + on a non-arithmetic type")
 
     | A.UNARY(A.ADDROF, e) -> begin
         match e with

test/small1/unary-plus-promotion.c

@@ -0,0 +1,13 @@
+#include "testharness.h"
+#include <stdlib.h>
+
+int main() {
+  char c;
+  size_t csize = sizeof(c);
+  size_t pluscsize = sizeof(+c);
+  if (csize != sizeof(char))
+    E(1);
+  if (pluscsize != sizeof(int))
+    E(2);
+  SUCCESS;
+}

test/testcil.pl

@@ -323,6 +323,7 @@ sub addToGroup {
 addTest("test_i/lineno");
 addTest("test/list");
 addTest("testrun/localinit ");
+addTest("testrun/unary-plus-promotion");
 
 addTest('testrun/longBlock', '');
 addTest("testrun/perror");