diff mbox series

middle-end/106617 - fix fold_binary_op_with_conditional_arg pattern issue

Message ID 20220818140411.B17FF3858C2D@sourceware.org
State New, archived
Headers
Series middle-end/106617 - fix fold_binary_op_with_conditional_arg pattern issue |

Commit Message

Richard Biener Aug. 18, 2022, 2:03 p.m. UTC 
  Now that we have parts of fold_binary_op_with_conditional_arg duplicated
in match.pd and are using ! to take or throw away the result we have to
be careful to not have both implementations play games which each other,
causing quadratic behavior.  In particular the match.pd implementation
requires both arms to simplify while the fold-const.cc is happy with
just one arm simplifying (something we cannot express in match.pd).

The fix is to simply not enable the match.pd pattern for GENERIC.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR middle-end/106617
	* match.pd ((a ? b : c) > d -> a ? (b > d) : (c > d)): Fix
	guard, disable on GENERIC to not cause quadratic behavior
	with the fold-const.cc implementation and the use of !

	* gcc.dg/pr106617.c: New testcase.
---
 gcc/match.pd                    |  4 +++-
 gcc/testsuite/gcc.dg/pr106617.c | 36 +++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr106617.c
diff mbox series

Patch

diff --git a/gcc/match.pd b/gcc/match.pd
index 07d0a61fc3a..1bb936fc401 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -5796,6 +5796,7 @@  DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (cmp (bit_and@2 @0 integer_pow2p@1) @1)
   (icmp @2 { build_zero_cst (TREE_TYPE (@0)); })))
 
+#if GIMPLE
 /* From fold_binary_op_with_conditional_arg handle the case of
    rewriting (a ? b : c) > d to a ? (b > d) : (c > d) when the
    compares simplify.  */
@@ -5805,8 +5806,9 @@  DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   /* Do not move possibly trapping operations into the conditional as this
      pessimizes code and causes gimplification issues when applied late.  */
   (if (!FLOAT_TYPE_P (TREE_TYPE (@3))
-       || operation_could_trap_p (cmp, true, false, @3))
+       || !operation_could_trap_p (cmp, true, false, @3))
    (cond @0 (cmp! @1 @3) (cmp! @2 @3)))))
+#endif
 
 (for cmp (ge lt)
 /* x < 0 ? ~y : y into (x >> (prec-1)) ^ y. */
diff --git a/gcc/testsuite/gcc.dg/pr106617.c b/gcc/testsuite/gcc.dg/pr106617.c
new file mode 100644
index 00000000000..4274b55f80d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106617.c
@@ -0,0 +1,36 @@ 
+/* { dg-do compile } */
+
+int nr_cpu_ids;
+void fc_setup_exch_mgr() {
+  (((((((1UL << (((0, 0)
+                            ? ((1)
+                                   ? (((nr_cpu_ids)) ? 0
+                                      : ((nr_cpu_ids)) & (21) ? 21
+                                      : ((nr_cpu_ids)) ? 20
+                                      : ((nr_cpu_ids)) & (19) ? 19
+                                      : ((nr_cpu_ids)) ? 18
+                                      : ((nr_cpu_ids)) & (17) ? 17
+                                      : ((nr_cpu_ids)) ? 16
+                                      : ((nr_cpu_ids)) & (15) ? 15
+                                      : ((nr_cpu_ids)) ? 14
+                                      : ((nr_cpu_ids)) & (13) ? 13
+                                      : ((nr_cpu_ids)) ? 12
+                                      : ((nr_cpu_ids)) & (11) ? 11
+                                      : ((nr_cpu_ids)) ? 10
+                                      : ((nr_cpu_ids)) & (9)  ? 9
+                                      : ((nr_cpu_ids))  ? 8
+                                      : ((nr_cpu_ids)) & (7)  ? 7
+                                      : ((nr_cpu_ids))  ? 6
+                                      : ((nr_cpu_ids)) & (5)  ? 5
+                                      : ((nr_cpu_ids))  ? 4
+                                      : ((nr_cpu_ids)) & (3)
+                                          ? 3
+                                          : ((nr_cpu_ids)-1) & 1)
+                                   : 1)
+                            : 0) +
+                       1))))) &
+                 (1UL << 2)
+             ? 2
+             : 1))
+           );
+}