compiler: Prohibit comparisons of funcs, maps, and slices to non-nil.

[pf3gnuchains/gcc-fork.git] / gcc / simplify-rtx.c

diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 1301616..6733b84 100644 (file)
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -2953,7 +2953,7 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
                }
            }
        }
-      else
+      else if (SCALAR_INT_MODE_P (mode))
        {
          /* 0/x is 0 (or x&0 if x has side-effects).  */
          if (trueop0 == CONST0_RTX (mode)
@@ -4352,10 +4352,20 @@ simplify_relational_operation_1 (enum rtx_code code, enum machine_mode mode,
     {
       rtx x = XEXP (op0, 0);
       rtx c = XEXP (op0, 1);
+      enum rtx_code invcode = op0code == PLUS ? MINUS : PLUS;
+      rtx tem = simplify_gen_binary (invcode, cmp_mode, op1, c);
+
+      /* Detect an infinite recursive condition, where we oscillate at this
+        simplification case between:
+           A + B == C  <--->  C - B == A,
+        where A, B, and C are all constants with non-simplifiable expressions,
+        usually SYMBOL_REFs.  */
+      if (GET_CODE (tem) == invcode
+         && CONSTANT_P (x)
+         && rtx_equal_p (c, XEXP (tem, 1)))
+       return NULL_RTX;
 
-      c = simplify_gen_binary (op0code == PLUS ? MINUS : PLUS,
-                              cmp_mode, op1, c);
-      return simplify_gen_relational (code, mode, cmp_mode, x, c);
+      return simplify_gen_relational (code, mode, cmp_mode, x, tem);
     }
 
   /* (ne:SI (zero_extract:SI FOO (const_int 1) BAR) (const_int 0))) is