For "(int) -x", which is a NOP_EXPR, negate_expr_p returns true, which means
that fold_negate_expr cannot return NULL_TREE. But that's what happens here,
leading to a crash in fold_build2. negate_expr_p has (as well as negate_expr)
STRIP_SIGN_NOPS, so the "(int) -x" becomes "-x", but fold_negate_expr doesn't
have any STRIP_SIGN_NOPS. Richi suggested to add a wrapper for fold_negate_expr
that strips/restores such NOP_EXPRs, much like negate_expr, which is what this
patch does.
Bootstrapped/regtested on x86_64-linux, ok for trunk? And 6 after a while?
2017-02-16 Marek Polacek <pola...@redhat.com>
PR middle-end/79536
* fold-const.c (fold_negate_expr_1): Renamed from fold_negate_expr.
(fold_negate_expr): New wrapper.
* gcc.dg/torture/pr79536.c: New test.
diff --git gcc/fold-const.c gcc/fold-const.c
index a8bb8af..ad4770b 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -139,6 +139,7 @@ static tree fold_relational_const (enum tree_code, tree,
tree, tree);
static tree fold_convert_const (enum tree_code, tree, tree);
static tree fold_view_convert_expr (tree, tree);
static bool vec_cst_ctor_to_array (tree, tree *);
+static tree fold_negate_expr (location_t, tree);
/* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
@@ -522,7 +523,7 @@ negate_expr_p (tree t)
returned. */
static tree
-fold_negate_expr (location_t loc, tree t)
+fold_negate_expr_1 (location_t loc, tree t)
{
tree type = TREE_TYPE (t);
tree tem;
@@ -533,7 +534,7 @@ fold_negate_expr (location_t loc, tree t)
case BIT_NOT_EXPR:
if (INTEGRAL_TYPE_P (type))
return fold_build2_loc (loc, PLUS_EXPR, type, TREE_OPERAND (t, 0),
- build_one_cst (type));
+ build_one_cst (type));
break;
case INTEGER_CST:
@@ -581,14 +582,14 @@ fold_negate_expr (location_t loc, tree t)
case COMPLEX_EXPR:
if (negate_expr_p (t))
return fold_build2_loc (loc, COMPLEX_EXPR, type,
- fold_negate_expr (loc, TREE_OPERAND (t, 0)),
- fold_negate_expr (loc, TREE_OPERAND (t, 1)));
+ fold_negate_expr (loc, TREE_OPERAND (t, 0)),
+ fold_negate_expr (loc, TREE_OPERAND (t, 1)));
break;
case CONJ_EXPR:
if (negate_expr_p (t))
return fold_build1_loc (loc, CONJ_EXPR, type,
- fold_negate_expr (loc, TREE_OPERAND (t, 0)));
+ fold_negate_expr (loc, TREE_OPERAND (t, 0)));
break;
case NEGATE_EXPR:
@@ -605,7 +606,7 @@ fold_negate_expr (location_t loc, tree t)
{
tem = negate_expr (TREE_OPERAND (t, 1));
return fold_build2_loc (loc, MINUS_EXPR, type,
- tem, TREE_OPERAND (t, 0));
+ tem, TREE_OPERAND (t, 0));
}
/* -(A + B) -> (-A) - B. */
@@ -613,7 +614,7 @@ fold_negate_expr (location_t loc, tree t)
{
tem = negate_expr (TREE_OPERAND (t, 0));
return fold_build2_loc (loc, MINUS_EXPR, type,
- tem, TREE_OPERAND (t, 1));
+ tem, TREE_OPERAND (t, 1));
}
}
break;
@@ -623,7 +624,7 @@ fold_negate_expr (location_t loc, tree t)
if (!HONOR_SIGN_DEPENDENT_ROUNDING (element_mode (type))
&& !HONOR_SIGNED_ZEROS (element_mode (type)))
return fold_build2_loc (loc, MINUS_EXPR, type,
- TREE_OPERAND (t, 1), TREE_OPERAND (t, 0));
+ TREE_OPERAND (t, 1), TREE_OPERAND (t, 0));
break;
case MULT_EXPR:
@@ -638,11 +639,11 @@ fold_negate_expr (location_t loc, tree t)
tem = TREE_OPERAND (t, 1);
if (negate_expr_p (tem))
return fold_build2_loc (loc, TREE_CODE (t), type,
- TREE_OPERAND (t, 0), negate_expr (tem));
+ TREE_OPERAND (t, 0), negate_expr (tem));
tem = TREE_OPERAND (t, 0);
if (negate_expr_p (tem))
return fold_build2_loc (loc, TREE_CODE (t), type,
- negate_expr (tem), TREE_OPERAND (t, 1));
+ negate_expr (tem), TREE_OPERAND (t, 1));
}
break;
@@ -715,6 +716,19 @@ fold_negate_expr (location_t loc, tree t)
return NULL_TREE;
}
+/* A wrapper for fold_negate_expr_1. */
+
+static tree
+fold_negate_expr (location_t loc, tree t)
+{
+ tree type = TREE_TYPE (t);
+ STRIP_SIGN_NOPS (t);
+ tree tem = fold_negate_expr_1 (loc, t);
+ if (tem == NULL_TREE)
+ return NULL_TREE;
+ return fold_convert_loc (loc, type, tem);
+}
+
/* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
negated in a simpler way. Also allow for T to be NULL_TREE, in which case
return NULL_TREE. */
diff --git gcc/testsuite/gcc.dg/torture/pr79536.c
gcc/testsuite/gcc.dg/torture/pr79536.c
index e69de29..6f05ca7 100644
--- gcc/testsuite/gcc.dg/torture/pr79536.c
+++ gcc/testsuite/gcc.dg/torture/pr79536.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+
+typedef int A;
+int
+fn1 (A x, A y)
+{
+ if ((x + (x - y) * 1i) != -(-x + (y - x) * 1i))
+ return 1;
+ return 0;
+}
Marek
