[PATCH] Fix ICE on _Fract division (PR tree-optimization/81428)

[Jakub Jelinek <jakub@redhat.com>]

Hi!

_Fract types can't express 1, other spots that call build_one_cst already
make sure that the type is integral or uses the !ALL_FRACT_MODE_P (TYPE_MODE (type))
check I've added in this patch.

Bootstrapped/regtested on x86_64-linux and i686-linux and tested with a
cross to arm on the testcase.  Ok for trunk?

2017-07-13  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/81428
	* match.pd (X / X -> one): Don't optimize _Fract divisions, as 1
	can't be built for those types.

	* gcc.dg/fixed-point/pr81428.c: New test.

--- gcc/match.pd.jj	2017-07-13 15:37:34.000000000 +0200
+++ gcc/match.pd	2017-07-13 15:46:11.194593051 +0200
@@ -243,8 +243,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  /* X / X is one.  */
  (simplify
   (div @0 @0)
-  /* But not for 0 / 0 so that we can get the proper warnings and errors.  */
-  (if (!integer_zerop (@0))
+  /* But not for 0 / 0 so that we can get the proper warnings and errors.
+     And not for _Fract types where we can't build 1.  */
+  (if (!integer_zerop (@0) && !ALL_FRACT_MODE_P (TYPE_MODE (type)))
    { build_one_cst (type); }))
  /* X / abs (X) is X < 0 ? -1 : 1.  */ 
  (simplify
--- gcc/testsuite/gcc.dg/fixed-point/pr81428.c.jj	2017-07-13 15:49:52.980806440 +0200
+++ gcc/testsuite/gcc.dg/fixed-point/pr81428.c	2017-07-13 15:49:29.000000000 +0200
@@ -0,0 +1,9 @@
+/* PR tree-optimization/81428 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void
+foo (long _Fract *a, long _Fract *b)
+{
+  *b = *a / *a;
+}

	Jakub