Recently on IRC we've concluded that for GCC 5 the simplest solution
will be to just disable the problematic pattern on GENERIC. So done
in the following. (The problem was that the match.pd pattern created
SAVE_EXPRs which then leaked into gimplification.)
Bootstrapped/regtested on x86_64-linux, ok for 5?
2016-01-19 Marek Polacek <pola...@redhat.com>
PR c/68513
* match.pd ((x & ~m) | (y & m)): Only perform on GIMPLE.
* gcc.dg/pr68513.c: New test.
diff --git gcc/match.pd gcc/match.pd
index e40720e..0b557e6 100644
--- gcc/match.pd
+++ gcc/match.pd
@@ -385,8 +385,9 @@ along with GCC; see the file COPYING3. If not see
/* (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x */
(simplify
(bit_ior:c (bit_and:c@3 @0 (bit_not @2)) (bit_and:c@4 @1 @2))
- (if ((TREE_CODE (@3) != SSA_NAME || has_single_use (@3))
- && (TREE_CODE (@4) != SSA_NAME || has_single_use (@4)))
+ (if (GIMPLE
+ && (TREE_CODE (@3) != SSA_NAME || has_single_use (@3))
+ && (TREE_CODE (@4) != SSA_NAME || has_single_use (@4)))
(bit_xor (bit_and (bit_xor @0 @1) @2) @0)))
diff --git gcc/testsuite/gcc.dg/pr68513.c gcc/testsuite/gcc.dg/pr68513.c
index e69de29..86f878d 100644
--- gcc/testsuite/gcc.dg/pr68513.c
+++ gcc/testsuite/gcc.dg/pr68513.c
@@ -0,0 +1,125 @@
+/* PR c/68513 */
+/* { dg-do compile } */
+/* { dg-options "-funsafe-math-optimizations -fno-math-errno -O
-Wno-div-by-zero" } */
+
+int i;
+unsigned u;
+volatile int *e;
+
+#define E (i ? *e : 0)
+
+/* Can't trigger some of them because operand_equal_p will return false
+ for side-effects. */
+
+/* (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x */
+int
+fn1 (void)
+{
+ int r = 0;
+ r += (short) (E & ~u | i & u);
+ r += -(short) (E & ~u | i & u);
+ r += (short) -(E & ~u | i & u);
+ return r;
+}
+
+/* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
+double
+fn2 (void)
+{
+ double r;
+ r = __builtin_sqrt (E) < __builtin_inf ();
+ return r;
+}
+
+/* sqrt(x) < c is the same as x >= 0 && x < c*c. */
+double
+fn3 (void)
+{
+ double r;
+ r = __builtin_sqrt (E) < 1.3;
+ return r;
+}
+
+/* copysign(x,y)*copysign(x,y) -> x*x. */
+double
+fn4 (double y, double x)
+{
+ return __builtin_copysign (E, y) * __builtin_copysign (E, y);
+}
+
+/* x <= +Inf is the same as x == x, i.e. !isnan(x). */
+int
+fn5 (void)
+{
+ return E <= __builtin_inf ();
+}
+
+/* Fold (A & ~B) - (A & B) into (A ^ B) - B. */
+int
+fn6 (void)
+{
+ return (i & ~E) - (i & E);
+}
+
+/* Fold (A & B) - (A & ~B) into B - (A ^ B). */
+int
+fn7 (void)
+{
+ return (i & E) - (i & ~E);
+}
+
+/* x + (x & 1) -> (x + 1) & ~1 */
+int
+fn8 (void)
+{
+ return E + (E & 1);
+}
+
+/* Simplify comparison of something with itself. */
+int
+fn9 (void)
+{
+ return E <= E | E >= E;
+}
+
+/* Fold (A & ~B) - (A & B) into (A ^ B) - B. */
+int
+fn10 (void)
+{
+ return (i & ~E) - (i & E);
+}
+
+/* abs(x)*abs(x) -> x*x. Should be valid for all types. */
+int
+fn11 (void)
+{
+ return __builtin_abs (E) * __builtin_abs (E);
+}
+
+/* (x | CST1) & CST2 -> (x & CST2) | (CST1 & CST2) */
+int
+fn12 (void)
+{
+ return (E | 11) & 12;
+}
+
+/* fold_range_test */
+int
+fn13 (const char *s)
+{
+ return s[E] != '\0' && s[E] != '/';
+}
+
+/* fold_comparison */
+int
+fn14 (void)
+{
+ return (!!i ? : (u *= E / 0)) >= (u = E);
+}
+
+/* fold_mult_zconjz */
+_Complex int
+fn15 (_Complex volatile int *z)
+{
+ return *z * ~*z;
+}
Marek
