[C] Fix ICE with ubsan instrumentation and EXCESS_PRECISION_EXPR (PR c/80097)

Submitted by Jakub Jelinek on March 20, 2017, 9:09 p.m.

Details

Message ID 20170320210925.GN11094@tucnak
State New
Headers show

Commit Message

Jakub Jelinek March 20, 2017, 9:09 p.m.
Hi!

The C fully folding code expects that EXCESS_PRECISION_EXPR is never
the rhs of a COMPOUND_EXPR, instead it should wrap the whole COMPOUND_EXPR
if needed.  The following patch does that, bootstrapped/regtested on
x86_64-linux and i686-linux, ok for trunk?

2017-03-20  Jakub Jelinek  <jakub@redhat.com>

	PR c/80097
	* c-typeck.c (build_binary_op): Add EXCESS_PRECISION_EXPR only around
	optional COMPOUND_EXPR with ubsan instrumentation.

	* gcc.dg/ubsan/pr80097.c: New test.


	Jakub

Comments

Joseph S. Myers March 20, 2017, 10:14 p.m.
On Mon, 20 Mar 2017, Jakub Jelinek wrote:

> Hi!
> 
> The C fully folding code expects that EXCESS_PRECISION_EXPR is never
> the rhs of a COMPOUND_EXPR, instead it should wrap the whole COMPOUND_EXPR
> if needed.  The following patch does that, bootstrapped/regtested on
> x86_64-linux and i686-linux, ok for trunk?

OK.

Patch hide | download patch | download mbox

--- gcc/c/c-typeck.c.jj	2017-03-16 17:18:24.000000000 +0100
+++ gcc/c/c-typeck.c	2017-03-20 08:59:37.515399725 +0100
@@ -11856,14 +11856,16 @@  build_binary_op (location_t location, en
   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
 	   && !in_late_binary_op)
     ret = note_integer_operands (ret);
-  if (semantic_result_type)
-    ret = build1 (EXCESS_PRECISION_EXPR, semantic_result_type, ret);
   protected_set_expr_location (ret, location);
 
   if (instrument_expr != NULL)
     ret = fold_build2 (COMPOUND_EXPR, TREE_TYPE (ret),
 		       instrument_expr, ret);
 
+  if (semantic_result_type)
+    ret = build1_loc (location, EXCESS_PRECISION_EXPR,
+		      semantic_result_type, ret);
+
   return ret;
 }
 
--- gcc/testsuite/gcc.dg/ubsan/pr80097.c.jj	2017-03-20 08:58:24.227483256 +0100
+++ gcc/testsuite/gcc.dg/ubsan/pr80097.c	2017-03-20 08:57:15.000000000 +0100
@@ -0,0 +1,10 @@ 
+/* PR c/80097 */
+/* { dg-do compile } */
+/* { dg-options "-std=c89 -fsanitize=float-divide-by-zero" } */
+
+int
+foo (double a)
+{
+  int b = (1 / a >= 1);
+  return b;
+}