From 6d87c306c6a44f8db81a9a9f2f5de4d943d5e57f Mon Sep 17 00:00:00 2001
From: Bernd Schmidt <bernds@redhat.com>
Date: Tue, 16 Feb 2016 14:42:59 +0000
Subject: [PATCH] Fix bswap optimization on big-endian (PR69714, 67781).
PR tree-optimization/69714
* tree-ssa-math-opts.c (find_bswap_or_nop): Revert previous change.
Return NULL if we have irrelevant high bytes on BIG_ENDIAN.
testsuite/
PR tree-optimization/69714
* gcc.dg/torture/pr69714.c: New test.
From-SVN: r233452
---
gcc/ChangeLog | 6 +
gcc/testsuite/ChangeLog | 7 +-
gcc/testsuite/gcc.dg/torture/pr69714.c | 156 +++++++++++++++++++++++++
gcc/tree-ssa-math-opts.c | 46 +++-----
4 files changed, 185 insertions(+), 30 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr69714.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d41547a2da02..741fbd095c60 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-02-16 Bernd Schmidt <bschmidt@redhat.com>
+
+ PR tree-optimization/69714
+ * tree-ssa-math-opts.c (find_bswap_or_nop): Revert previous change.
+ Return NULL if we have irrelevant high bytes on BIG_ENDIAN.
+
2016-02-16 Claudiu Zissulescu <claziss@synopsys.com>
* config/arc/arc-modes.def (CC_FPU, CC_FPU_UNEQ): New modes.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4d6884ed5c49..38751605e80a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-02-16 Bernd Schmidt <bschmidt@redhat.com>
+
+ PR tree-optimization/69714
+ * gcc.dg/torture/pr69714.c: New test.
+
2016-02-16 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/69802
@@ -152,7 +157,7 @@
2016-02-12 Bernd Schmidt <bschmidt@redhat.com>
PR c/69522
- gcc.dg/pr69522.c: New test.
+ * gcc.dg/pr69522.c: New test.
2016-02-12 Patrick Palka <ppalka@gcc.gnu.org>
diff --git a/gcc/testsuite/gcc.dg/torture/pr69714.c b/gcc/testsuite/gcc.dg/torture/pr69714.c
new file mode 100644
index 000000000000..229b7ad58a11
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr69714.c
@@ -0,0 +1,156 @@
+/* { dg-do run } */
+/* { dg-options "-fno-strict-aliasing" } */
+
+#include <stdint.h>
+#include <stdio.h>
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define av_le2ne32(x) (x)
+#else
+#define av_le2ne32(x) av_bswap32(x)
+#endif
+
+static __attribute__((always_inline)) inline __attribute__((const)) uint32_t av_bswap32(uint32_t x)
+{
+ return ((((x) << 8 & 0xff00) | ((x) >> 8 & 0x00ff)) << 16 | ((((x) >> 16) << 8 & 0xff00) | (((x) >> 16) >> 8 & 0x00ff)));
+}
+
+typedef uint32_t AVCRC;
+
+typedef enum {
+ AV_CRC_8_ATM,
+ AV_CRC_16_ANSI,
+ AV_CRC_16_CCITT,
+ AV_CRC_32_IEEE,
+ AV_CRC_32_IEEE_LE,
+ AV_CRC_16_ANSI_LE,
+ AV_CRC_24_IEEE = 12,
+ AV_CRC_MAX,
+} AVCRCId;
+
+int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size);
+
+
+
+
+
+
+uint32_t av_crc(const AVCRC *ctx, uint32_t crc,
+ const uint8_t *buffer, size_t length) __attribute__((pure));
+static struct {
+ uint8_t le;
+ uint8_t bits;
+ uint32_t poly;
+} av_crc_table_params[AV_CRC_MAX] = {
+ [AV_CRC_8_ATM] = { 0, 8, 0x07 },
+ [AV_CRC_16_ANSI] = { 0, 16, 0x8005 },
+ [AV_CRC_16_CCITT] = { 0, 16, 0x1021 },
+ [AV_CRC_24_IEEE] = { 0, 24, 0x864CFB },
+ [AV_CRC_32_IEEE] = { 0, 32, 0x04C11DB7 },
+ [AV_CRC_32_IEEE_LE] = { 1, 32, 0xEDB88320 },
+ [AV_CRC_16_ANSI_LE] = { 1, 16, 0xA001 },
+};
+static AVCRC av_crc_table[AV_CRC_MAX][1024];
+
+
+int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size)
+{
+ unsigned i, j;
+ uint32_t c;
+
+ if (bits < 8 || bits > 32 || poly >= (1LL << bits))
+ return -1;
+ if (ctx_size != sizeof(AVCRC) * 257 && ctx_size != sizeof(AVCRC) * 1024)
+ return -1;
+
+ for (i = 0; i < 256; i++) {
+ if (le) {
+ for (c = i, j = 0; j < 8; j++)
+ c = (c >> 1) ^ (poly & (-(c & 1)));
+ ctx[i] = c;
+ } else {
+ for (c = i << 24, j = 0; j < 8; j++)
+ c = (c << 1) ^ ((poly << (32 - bits)) & (((int32_t) c) >> 31));
+ ctx[i] = av_bswap32(c);
+ }
+ }
+ ctx[256] = 1;
+
+ if (ctx_size >= sizeof(AVCRC) * 1024)
+ for (i = 0; i < 256; i++)
+ for (j = 0; j < 3; j++)
+ ctx[256 *(j + 1) + i] =
+ (ctx[256 * j + i] >> 8) ^ ctx[ctx[256 * j + i] & 0xFF];
+
+
+ return 0;
+}
+
+const AVCRC *av_crc_get_table(AVCRCId crc_id)
+{
+ if (!av_crc_table[crc_id][(sizeof(av_crc_table[crc_id]) / sizeof((av_crc_table[crc_id])[0])) - 1])
+ if (av_crc_init(av_crc_table[crc_id],
+ av_crc_table_params[crc_id].le,
+ av_crc_table_params[crc_id].bits,
+ av_crc_table_params[crc_id].poly,
+ sizeof(av_crc_table[crc_id])) < 0)
+ return ((void *)0);
+
+ return av_crc_table[crc_id];
+}
+
+uint32_t av_crc(const AVCRC *ctx, uint32_t crc,
+ const uint8_t *buffer, size_t length)
+{
+ const uint8_t *end = buffer + length;
+
+
+ if (!ctx[256]) {
+ while (((intptr_t) buffer & 3) && buffer < end)
+ crc = ctx[((uint8_t) crc) ^ *buffer++] ^ (crc >> 8);
+
+ while (buffer < end - 3) {
+ crc ^= av_le2ne32(*(const uint32_t *) buffer); buffer += 4;
+ crc = ctx[3 * 256 + ( crc & 0xFF)] ^
+ ctx[2 * 256 + ((crc >> 8 ) & 0xFF)] ^
+ ctx[1 * 256 + ((crc >> 16) & 0xFF)] ^
+ ctx[0 * 256 + ((crc >> 24) )];
+ }
+ }
+
+ while (buffer < end)
+ crc = ctx[((uint8_t) crc) ^ *buffer++] ^ (crc >> 8);
+
+ return crc;
+}
+
+
+int main(void)
+{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ || __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+ uint8_t buf[1999];
+ int i;
+ unsigned
+ p[6][3] = { { AV_CRC_32_IEEE_LE, 0xEDB88320, 0x3D5CDD04 },
+ { AV_CRC_32_IEEE , 0x04C11DB7, 0xE0BAF5C0 },
+ { AV_CRC_24_IEEE , 0x864CFB , 0x326039 },
+ { AV_CRC_16_ANSI_LE, 0xA001 , 0xBFD8 },
+ { AV_CRC_16_ANSI , 0x8005 , 0xBB1F },
+ { AV_CRC_8_ATM , 0x07 , 0xE3 }
+ };
+ const AVCRC *ctx;
+
+ for (i = 0; i < sizeof(buf); i++)
+ buf[i] = i + i * i;
+
+ for (i = 0; i < 6; i++) {
+ int id = p[i][0];
+ uint32_t result;
+ ctx = av_crc_get_table (id);
+ result = av_crc(ctx, 0, buf, sizeof(buf));
+ if (result != p[i][2])
+ __builtin_abort ();
+ }
+#endif
+ return 0;
+}
diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
index 3aa4a07435f9..2215b4dc7092 100644
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -2449,11 +2449,9 @@ find_bswap_or_nop_1 (gimple *stmt, struct symbolic_number *n, int limit)
static gimple *
find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
{
- unsigned rsize;
- uint64_t tmpn, mask;
-/* The number which the find_bswap_or_nop_1 result should match in order
- to have a full byte swap. The number is shifted to the right
- according to the size of the symbolic number before using it. */
+ /* The number which the find_bswap_or_nop_1 result should match in order
+ to have a full byte swap. The number is shifted to the right
+ according to the size of the symbolic number before using it. */
uint64_t cmpxchg = CMPXCHG;
uint64_t cmpnop = CMPNOP;
@@ -2474,38 +2472,28 @@ find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
/* Find real size of result (highest non-zero byte). */
if (n->base_addr)
- for (tmpn = n->n, rsize = 0; tmpn; tmpn >>= BITS_PER_MARKER, rsize++);
- else
- rsize = n->range;
+ {
+ unsigned HOST_WIDE_INT rsize;
+ uint64_t tmpn;
- /* Zero out the bits corresponding to untouched bytes in original gimple
- expression. */
+ for (tmpn = n->n, rsize = 0; tmpn; tmpn >>= BITS_PER_MARKER, rsize++);
+ if (BYTES_BIG_ENDIAN && n->range != rsize)
+ /* This implies an offset, which is currently not handled by
+ bswap_replace. */
+ return NULL;
+ n->range = rsize;
+ }
+
+ /* Zero out the extra bits of N and CMP*. */
if (n->range < (int) sizeof (int64_t))
{
+ uint64_t mask;
+
mask = ((uint64_t) 1 << (n->range * BITS_PER_MARKER)) - 1;
cmpxchg >>= (64 / BITS_PER_MARKER - n->range) * BITS_PER_MARKER;
cmpnop &= mask;
}
- /* Zero out the bits corresponding to unused bytes in the result of the
- gimple expression. */
- if (rsize < n->range)
- {
- if (BYTES_BIG_ENDIAN)
- {
- mask = ((uint64_t) 1 << (rsize * BITS_PER_MARKER)) - 1;
- cmpxchg &= mask;
- cmpnop >>= (n->range - rsize) * BITS_PER_MARKER;
- }
- else
- {
- mask = ((uint64_t) 1 << (rsize * BITS_PER_MARKER)) - 1;
- cmpxchg >>= (n->range - rsize) * BITS_PER_MARKER;
- cmpnop &= mask;
- }
- n->range = rsize;
- }
-
/* A complete byte swap should make the symbolic number to start with
the largest digit in the highest order byte. Unchanged symbolic
number indicates a read with same endianness as target architecture. */