re PR middle-end/70992 (Infinite recursion between fold_build2_stat_loc and fold_binary_loc w/ -fwrapv)

	PR middle-end/70992
	* tree.c (build2_stat): Don't set TREE_CONSTANT on divisions by zero.

	* gcc.dg/overflow-warn-1.c: Adjust dg-error.
	* gcc.dg/overflow-warn-2.c: Likewise.
	* gcc.dg/overflow-warn-3.c: Likewise.
	* gcc.dg/overflow-warn-4.c: Likewise.
	* gcc.dg/torture/pr70992-2.c: New test.
	* gcc.dg/torture/pr70992.c: New test.

From-SVN: r250566

9 files changed, 89 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ff746ff..fa34e49 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2017-07-26  Marek Polacek  <polacek@redhat.com>
+
+	PR middle-end/70992
+	* tree.c (build2_stat): Don't set TREE_CONSTANT on divisions by zero.
+
 2017-07-26  Richard Biener  <rguenther@suse.de>
 
 	* gimple-match-head.c (do_valueize): Return OP if valueize
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index aaec07c..b311c6a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2017-07-26  Marek Polacek  <polacek@redhat.com>
+
+	PR middle-end/70992
+	* gcc.dg/overflow-warn-1.c: Adjust dg-error.
+	* gcc.dg/overflow-warn-2.c: Likewise.
+	* gcc.dg/overflow-warn-3.c: Likewise.
+	* gcc.dg/overflow-warn-4.c: Likewise.
+	* gcc.dg/torture/pr70992-2.c: New test.
+	* gcc.dg/torture/pr70992.c: New test.
+
 2017-07-26  Richard Biener  <rguenther@suse.de>
 
 	* gcc/testsuite/gcc.dg/pr70920-2.c: Adjust for transform already
diff --git a/gcc/testsuite/gcc.dg/overflow-warn-1.c b/gcc/testsuite/gcc.dg/overflow-warn-1.c
index 8eb3225..a5cd573 100644
--- a/gcc/testsuite/gcc.dg/overflow-warn-1.c
+++ b/gcc/testsuite/gcc.dg/overflow-warn-1.c
@@ -49,7 +49,7 @@ static int sc = INT_MAX + 1; /* { dg-warning "25:integer overflow in expression"
 void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" } */
 /* { dg-warning "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-1 } */
 void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
-/* { dg-error "initializer element is not computable at load time" "constant" { target *-*-* } .-1 } */
+/* { dg-error "initializer element is not constant" "constant" { target *-*-* } .-1 } */
 /* { dg-warning "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
 void *r = (1 ? 0 : INT_MAX+1);
 
diff --git a/gcc/testsuite/gcc.dg/overflow-warn-2.c b/gcc/testsuite/gcc.dg/overflow-warn-2.c
index f048d6d..05ab104 100644
--- a/gcc/testsuite/gcc.dg/overflow-warn-2.c
+++ b/gcc/testsuite/gcc.dg/overflow-warn-2.c
@@ -49,7 +49,7 @@ static int sc = INT_MAX + 1; /* { dg-warning "integer overflow in expression" }
 void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" } */
 /* { dg-warning "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-1 } */
 void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
-/* { dg-error "initializer element is not computable at load time" "constant" { target *-*-* } .-1 } */
+/* { dg-error "initializer element is not constant" "constant" { target *-*-* } .-1 } */
 /* { dg-warning "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
 void *r = (1 ? 0 : INT_MAX+1);
 
diff --git a/gcc/testsuite/gcc.dg/overflow-warn-3.c b/gcc/testsuite/gcc.dg/overflow-warn-3.c
index 664011e4..fd4a34f 100644
--- a/gcc/testsuite/gcc.dg/overflow-warn-3.c
+++ b/gcc/testsuite/gcc.dg/overflow-warn-3.c
@@ -55,7 +55,7 @@ void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" }
 /* { dg-warning "overflow in constant expression" "constant" { target *-*-* } .-1 } */
 /* { dg-warning "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
 void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
-/* { dg-error "initializer element is not computable at load time" "constant" { target *-*-* } .-1 } */
+/* { dg-error "initializer element is not constant" "constant" { target *-*-* } .-1 } */
 /* { dg-warning "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
 void *r = (1 ? 0 : INT_MAX+1);
 
diff --git a/gcc/testsuite/gcc.dg/overflow-warn-4.c b/gcc/testsuite/gcc.dg/overflow-warn-4.c
index 52677ce..018e3e1 100644
--- a/gcc/testsuite/gcc.dg/overflow-warn-4.c
+++ b/gcc/testsuite/gcc.dg/overflow-warn-4.c
@@ -55,7 +55,7 @@ void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" }
 /* { dg-error "overflow in constant expression" "constant" { target *-*-* } .-1 } */
 /* { dg-error "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
 void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
-/* { dg-error "initializer element is not computable at load time" "constant" { target *-*-* } .-1 } */
+/* { dg-error "initializer element is not constant" "constant" { target *-*-* } .-1 } */
 /* { dg-error "initialization makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
 void *r = (1 ? 0 : INT_MAX+1);
 
diff --git a/gcc/testsuite/gcc.dg/torture/pr70992-2.c b/gcc/testsuite/gcc.dg/torture/pr70992-2.c
new file mode 100644
index 0000000..c5d2c5f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr70992-2.c
@@ -0,0 +1,9 @@
+/* PR middle-end/70992 */
+/* { dg-do compile } */
+
+unsigned int *od;
+int
+fn (void)
+{
+  return (0 % 0 + 1) * *od * 2; /* { dg-warning "division by zero" } */
+}
diff --git a/gcc/testsuite/gcc.dg/torture/pr70992.c b/gcc/testsuite/gcc.dg/torture/pr70992.c
new file mode 100644
index 0000000..56728e0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr70992.c
@@ -0,0 +1,41 @@
+/* PR middle-end/70992 */
+/* { dg-do compile } */
+
+typedef unsigned int uint32_t;
+typedef int int32_t;
+
+uint32_t
+fn (uint32_t so)
+{
+  return (so + so) * (0x80000000 / 0 + 1); /* { dg-warning "division by zero" } */
+}
+
+uint32_t
+fn5 (uint32_t so)
+{
+  return (0x80000000 / 0 + 1) * (so + so); /* { dg-warning "division by zero" } */
+}
+
+uint32_t
+fn6 (uint32_t so)
+{
+  return (0x80000000 / 0 - 1) * (so + so); /* { dg-warning "division by zero" } */
+}
+
+uint32_t
+fn2 (uint32_t so)
+{
+  return (so + so) * (0x80000000 / 0 - 1); /* { dg-warning "division by zero" } */
+}
+
+int32_t
+fn3 (int32_t so)
+{
+  return (so + so) * (0x80000000 / 0 + 1); /* { dg-warning "division by zero" } */
+}
+
+int32_t
+fn4 (int32_t so)
+{
+  return (so + so) * (0x80000000 / 0 - 1); /* { dg-warning "division by zero" } */
+}
diff --git a/gcc/tree.c b/gcc/tree.c
index b7de284..48fb2ce 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -4456,7 +4456,7 @@ build1_stat (enum tree_code code, tree type, tree node MEM_STAT_DECL)
 tree
 build2_stat (enum tree_code code, tree tt, tree arg0, tree arg1 MEM_STAT_DECL)
 {
-  bool constant, read_only, side_effects;
+  bool constant, read_only, side_effects, div_by_zero;
   tree t;
 
   gcc_assert (TREE_CODE_LENGTH (code) == 2);
@@ -4489,6 +4489,23 @@ build2_stat (enum tree_code code, tree tt, tree arg0, tree arg1 MEM_STAT_DECL)
   read_only = 1;
   side_effects = TREE_SIDE_EFFECTS (t);
 
+  switch (code)
+    {
+    case TRUNC_DIV_EXPR:
+    case CEIL_DIV_EXPR:
+    case FLOOR_DIV_EXPR:
+    case ROUND_DIV_EXPR:
+    case EXACT_DIV_EXPR:
+    case CEIL_MOD_EXPR:
+    case FLOOR_MOD_EXPR:
+    case ROUND_MOD_EXPR:
+    case TRUNC_MOD_EXPR:
+      div_by_zero = integer_zerop (arg1);
+      break;
+    default:
+      div_by_zero = false;
+    }
+
   PROCESS_ARG (0);
   PROCESS_ARG (1);
 
@@ -4505,7 +4522,8 @@ build2_stat (enum tree_code code, tree tt, tree arg0, tree arg1 MEM_STAT_DECL)
   else
     {
       TREE_READONLY (t) = read_only;
-      TREE_CONSTANT (t) = constant;
+      /* Don't mark X / 0 as constant.  */
+      TREE_CONSTANT (t) = constant && !div_by_zero;
       TREE_THIS_VOLATILE (t)
 	= (TREE_CODE_CLASS (code) == tcc_reference
 	   && arg0 && TREE_THIS_VOLATILE (arg0));