[PATCH] Fix PR86271

[Richard Biener]

The following fixes the bogus IL that does pointer extension
from inlining of mismatched function args (testcase with -m32).

The solution as implemented is to not inline by making
fold_convertible reject the required conversion.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2018-06-25  Richard Biener  <rguent...@suse.de>

        PR middle-end/86271
        * fold-const.c (fold_convertible_p): Pointer extension
        isn't valid.

        * gcc.dg/pr86271.c: New testcase.

Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c    (revision 262006)
+++ gcc/fold-const.c    (working copy)
@@ -2358,7 +2358,9 @@ fold_convertible_p (const_tree type, con
     case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
     case POINTER_TYPE: case REFERENCE_TYPE:
     case OFFSET_TYPE:
-      return (INTEGRAL_TYPE_P (orig) || POINTER_TYPE_P (orig)
+      return (INTEGRAL_TYPE_P (orig)
+             || (POINTER_TYPE_P (orig)
+                 && TYPE_PRECISION (type) <= TYPE_PRECISION (orig))
              || TREE_CODE (orig) == OFFSET_TYPE);
 
     case REAL_TYPE:
Index: gcc/testsuite/gcc.dg/pr86271.c
===================================================================
--- gcc/testsuite/gcc.dg/pr86271.c      (nonexistent)
+++ gcc/testsuite/gcc.dg/pr86271.c      (working copy)
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int main ()
+{
+  int i;
+  foobar (i, &i); /* { dg-warning "implicit declaration" } */
+}
+
+int foobar (int a, long long b)
+{
+  int c;
+
+  c = a % b;
+  a = a / b;
+  return a + b;
+}