> From: Jakub Jelinek [mailto:ja...@redhat.com] > > In theory you could have __CHAR_BIT__ different from 8 and what you care > about is that uint32_t has exactly 32 bits, so the check would need to be > if (sizeof (uint32_t) * __CHAR_BIT__ != 32) > return 0;
I could go with:
In = (0x12 << (__CHAR_BIT__ * 3))
| (0x34 << (__CHAR_BIT__ * 2))
| (0x56 << __CHAR_BIT__)
| 0x78;
and compare with a similarly constructed out so that I could run the test
whenever sizeof (uint32_t) * __CHAR_BIT__ >= 32, isn't it?
>
> Also, for int16 targets where __UINT32_TYPE__ is supposedly unsigned long,
> I think you would need to use:
>
> if (fake_swap32 (0x12345678UL) != 0x78567E12UL)
> __builtin_abort ();
>
> (the C standard guarantees that unsigned long is at least 32-bit and
> unsigned int at least 16-bit).
Right. Note to myself: ยง5.2.4.2.1 in C99. I guess so far I've only considered
only some kind of architecture heterogeneity. Thanks for catching that.
>
> Ok with those changes.
>
> Do you have write access, or will somebody from your coworkers commit it
> for
> you? Are you covered by ARM GCC Copyright assignment?
Yes and yes.
>
> Jakub
Thanks for the review. See attachment and below to check the version you
approved.
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 748805e..b6d7d93 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2014-03-07 Thomas Preud'homme <thomas.preudho...@arm.com>
+
+ PR tree-optimization/60454
+ * tree-ssa-math-opts.c (find_bswap_1): Fix bswap detection.
+
2014-02-23 David Holsgrove <david.holsgr...@xilinx.com>
* config/microblaze/microblaze.md: Correct ashrsi_reg / lshrsi_reg names
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f3c0c85..04ce403 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-03-10 Thomas Preud'homme <thomas.preudho...@arm.com>
+
+ PR tree-optimization/60454
+ * gcc.c-torture/execute/pr60454.c: New test.
+
2014-02-23 David Holsgrove <david.holsgr...@xilinx.com>
* gcc/testsuite/gcc.target/microblaze/others/mem_reload.c: New test.
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr60454.c
b/gcc/testsuite/gcc.c-torture/execute/pr60454.c
new file mode 100644
index 0000000..ceec45e
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr60454.c
@@ -0,0 +1,31 @@
+#ifdef __UINT32_TYPE__
+typedef __UINT32_TYPE__ uint32_t;
+#else
+typedef unsigned uint32_t;
+#endif
+
+#define __fake_const_swab32(x) ((uint32_t)( \
+ (((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \
+ (((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) | \
+ (((uint32_t)(x) & (uint32_t)0x000000ffUL) << 8) | \
+ (((uint32_t)(x) & (uint32_t)0x0000ff00UL) ) | \
+ (((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24)))
+
+/* Previous version of bswap optimization would detect byte swap when none
+ happen. This test aims at catching such wrong detection to avoid
+ regressions. */
+
+__attribute__ ((noinline, noclone)) uint32_t
+fake_swap32 (uint32_t in)
+{
+ return __fake_const_swab32 (in);
+}
+
+int main(void)
+{
+ if (sizeof (uint32_t) * __CHAR_BIT__ != 32)
+ return 0;
+ if (fake_swap32 (0x12345678UL) != 0x78567E12UL)
+ __builtin_abort ();
+ return 0;
+}
diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
index 8e372ed..9ff857c 100644
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -1801,7 +1801,9 @@ find_bswap_1 (gimple stmt, struct symbolic_number *n, int
limit)
if (rhs_class == GIMPLE_BINARY_RHS)
{
+ int i;
struct symbolic_number n1, n2;
+ unsigned HOST_WIDEST_INT mask;
tree source_expr2;
if (code != BIT_IOR_EXPR)
@@ -1827,6 +1829,15 @@ find_bswap_1 (gimple stmt, struct symbolic_number *n,
int limit)
return NULL_TREE;
n->size = n1.size;
+ for (i = 0, mask = 0xff; i < n->size; i++, mask <<= BITS_PER_UNIT)
+ {
+ unsigned HOST_WIDEST_INT masked1, masked2;
+
+ masked1 = n1.n & mask;
+ masked2 = n2.n & mask;
+ if (masked1 && masked2 && masked1 != masked2)
+ return NULL_TREE;
+ }
n->n = n1.n | n2.n;
if (!verify_symbolic_number_p (n, stmt))
Best regards,
Thomas
incorrect_detection_v1.5.diff
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