The following fixes recursion between a pattern in fold-const.c and
one formerly in tree-ssa-forwprop.c but now in match.pd (and thus
also fold-const.c). There are two conflicting transforms and the
measure against recursion I put in place doesn't help for the
testcase (as the conversion is useless).
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Richard.
2014-11-07 Richard Biener <rguent...@suse.de>
PR middle-end/63770
* match.pd: Guard conflicting GENERIC pattern properly.
* gcc.dg/pr63770.c: New testcase.
Index: gcc/match.pd
===================================================================
--- gcc/match.pd 2014-11-07 09:24:45.943027082 +0100
+++ gcc/match.pd 2014-11-07 09:23:06.573031431 +0100
@@ -129,14 +129,15 @@ along with GCC; see the file COPYING3.
(bitop (convert @0) (convert? @1))
(if (((TREE_CODE (@1) == INTEGER_CST
&& INTEGRAL_TYPE_P (TREE_TYPE (@0))
- && int_fits_type_p (@1, TREE_TYPE (@0))
- /* ??? This transform conflicts with fold-const.c doing
- Convert (T)(x & c) into (T)x & (T)c, if c is an integer
- constants (if x has signed type, the sign bit cannot be set
- in c). This folds extension into the BIT_AND_EXPR.
- Restrict it to GIMPLE to avoid endless recursions. */
- && (bitop != BIT_AND_EXPR || GIMPLE))
- || types_compatible_p (TREE_TYPE (@0), TREE_TYPE (@1)))
+ && int_fits_type_p (@1, TREE_TYPE (@0)))
+ || (GIMPLE && types_compatible_p (TREE_TYPE (@0), TREE_TYPE (@1)))
+ || (GENERIC && TREE_TYPE (@0) == TREE_TYPE (@1)))
+ /* ??? This transform conflicts with fold-const.c doing
+ Convert (T)(x & c) into (T)x & (T)c, if c is an integer
+ constants (if x has signed type, the sign bit cannot be set
+ in c). This folds extension into the BIT_AND_EXPR.
+ Restrict it to GIMPLE to avoid endless recursions. */
+ && (bitop != BIT_AND_EXPR || GIMPLE)
&& (/* That's a good idea if the conversion widens the operand, thus
after hoisting the conversion the operation will be narrower. */
TYPE_PRECISION (TREE_TYPE (@0)) < TYPE_PRECISION (type)
Index: gcc/testsuite/gcc.dg/pr63770.c
===================================================================
--- gcc/testsuite/gcc.dg/pr63770.c (revision 0)
+++ gcc/testsuite/gcc.dg/pr63770.c (working copy)
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+
+char a;
+
+struct S
+{
+ int f0:9;
+};
+
+volatile struct S b;
+
+int
+fn1 ()
+{
+ return (1 & b.f0) < a;
+}
