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[PATCH] Fix do_jump (PR middle-end/40057)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 7 May 2009 16:52:04 +0200
- Subject: [PATCH] Fix do_jump (PR middle-end/40057)
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
The following testcase is miscompiled with i?86-linux 32-bit HWI cc1, but
not with 64-bit HWI x86_64-linux cc1 with -m32.
The problem is that do_jump creates the (supposed to be 1 bit) mask with
build_int_cst_type, if shift is HOST_BITS_PER_WIDE_INT - 1, then mask
is a negative HOST_WIDE_INT number and so for long long has 33 bits set, not
just 1. Fixed by using build_int_cst_wide_type instead.
Also, prefer_and_bit_test has a similar bug, for 32-bit HWI and bitnum 31
we want to create CONST_DOUBLE 2147483648, not CONST_INT -2147483648.
Bootstrapped/regtested on i686-linux and x86_64-linux, ok for trunk/4.4?
2009-05-07 Jakub Jelinek <jakub@redhat.com>
PR middle-end/40057
* dojump.c (prefer_and_bit_test): Use immed_double_const instead of
GEN_INT for 1 << bitnum.
(do_jump) <case BIT_AND_EXPR>: Use build_int_cst_wide_type instead of
build_int_cst_type.
* gcc.c-torture/execute/pr40057.c: New test.
--- gcc/dojump.c.jj 2009-04-24 21:41:28.000000000 +0200
+++ gcc/dojump.c 2009-05-07 14:54:05.000000000 +0200
@@ -141,7 +141,8 @@ prefer_and_bit_test (enum machine_mode m
}
/* Fill in the integers. */
- XEXP (and_test, 1) = GEN_INT ((unsigned HOST_WIDE_INT) 1 << bitnum);
+ XEXP (and_test, 1)
+ = immed_double_const ((unsigned HOST_WIDE_INT) 1 << bitnum, 0, mode);
XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum);
return (rtx_cost (and_test, IF_THEN_ELSE, optimize_insn_for_speed_p ())
@@ -475,10 +476,10 @@ do_jump (tree exp, rtx if_false_label, r
&& prefer_and_bit_test (TYPE_MODE (argtype),
TREE_INT_CST_LOW (shift)))
{
- HOST_WIDE_INT mask = (HOST_WIDE_INT) 1
- << TREE_INT_CST_LOW (shift);
+ unsigned HOST_WIDE_INT mask
+ = (unsigned HOST_WIDE_INT) 1 << TREE_INT_CST_LOW (shift);
do_jump (build2 (BIT_AND_EXPR, argtype, arg,
- build_int_cst_type (argtype, mask)),
+ build_int_cst_wide_type (argtype, mask, 0)),
clr_label, set_label);
break;
}
--- gcc/testsuite/gcc.c-torture/execute/pr40057.c.jj 2009-05-07 15:07:59.000000000 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr40057.c 2009-05-07 15:05:54.000000000 +0200
@@ -0,0 +1,37 @@
+/* PR middle-end/40057 */
+
+extern void abort (void);
+
+__attribute__((noinline)) int
+foo (unsigned long long x)
+{
+ unsigned long long y = (x >> 31ULL) & 1ULL;
+ if (y == 0ULL)
+ return 0;
+ return -1;
+}
+
+__attribute__((noinline)) int
+bar (long long x)
+{
+ long long y = (x >> 31LL) & 1LL;
+ if (y == 0LL)
+ return 0;
+ return -1;
+}
+
+int
+main (void)
+{
+ if (sizeof (long long) != 8)
+ return 0;
+ if (foo (0x1682a9aaaULL))
+ abort ();
+ if (!foo (0x1882a9aaaULL))
+ abort ();
+ if (bar (0x1682a9aaaLL))
+ abort ();
+ if (!bar (0x1882a9aaaLL))
+ abort ();
+ return 0;
+}
Jakub