[ifcombine] fix mask variable test to match use [PR118344]

There was a cut&pasto in the rr_and_mask's adjustment to match the
combined type: the test on whether there was a mask already was
testing the wrong variable, and then it might crash or otherwise fail
accessing an undefined mask.  This only hit with checking enabled,
and rarely at that.


for  gcc/ChangeLog

	PR tree-optimization/118344
	* gimple-fold.cc (fold_truth_andor_for_ifcombine): Fix typo in
	rr_and_mask's type adjustment test.

for  gcc/testsuite/ChangeLog

	PR tree-optimization/118344
	* gcc.dg/field-merge-19.c: New.

2 files changed, 42 insertions, 1 deletions

diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index 0ad92de..20b5024 100644
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -8644,7 +8644,7 @@ fold_truth_andor_for_ifcombine (enum tree_code code, tree truth_type,
 			  xlr_bitpos);
       else
 	lr_mask = wi::shifted_mask (xlr_bitpos, lr_bitsize, false, rnprec);
-      if (rl_and_mask.get_precision ())
+      if (rr_and_mask.get_precision ())
 	rr_mask = wi::lshift (wide_int::from (rr_and_mask, rnprec, UNSIGNED),
 			      xrr_bitpos);
       else
diff --git a/gcc/testsuite/gcc.dg/field-merge-19.c b/gcc/testsuite/gcc.dg/field-merge-19.c
new file mode 100644
index 0000000..5622baa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/field-merge-19.c
@@ -0,0 +1,41 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fchecking" } */
+
+/* PR tree-optimization/118344 */
+
+/* This used to ICE attempting to extend a mask variable after testing the
+   wrong mask variable.  */
+
+int d, e, g, h, i, c, j;
+static short k;
+char o;
+static int *p;
+static long *a;
+int b[0];
+int q(int s, int t, int *u, int *v) {
+  for (int f = 0; f < s; f++)
+    if ((t & v[f]) != u[f])
+      return 0;
+  return 1;
+}
+int w(int s, int t) {
+  int l[] = {t, t, t, t}, m[] = {e, e, 3, 1};
+  int n = q(s, d, l, m);
+  return n;
+}
+int x(unsigned s) {
+  unsigned r;
+  if (s >= -1)
+    return 1;
+  r = 10000000;
+  while (s > 1 / r)
+    r /= 2;
+  return g ? 2 : 0;
+}
+void y() {
+  for (;;) {
+    b[w(8, *p)] = h;
+    for (; a + k; j = o)
+      i &= c = x(6) < 0;
+  }
+}