re PR target/66648 (incorrect memcpy expansion with unrolled_loop strategy at -O2)

	PR target/66648
	* config/i386/i386.c (ix86_expand_set_or_movmem): Emit main loop
	execution guard when min_size is less than size_needed.

testsuite/ChangeLog:

	PR target/66648
	* gcc.target/i386/pr66648.c: New test.

From-SVN: r226212

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e70f931288129f436f783e66cae30c89e9c22592..60c4adec35fc43542e986d137ab817cd73f28c6a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-07-25  Uros Bizjak  <ubizjak@gmail.com>
+
+       PR target/66648
+       * config/i386/i386.c (ix86_expand_set_or_movmem): Emit main loop
+       execution guard when min_size is less than size_needed.
+
 2015-07-25  Sebastian Pop  <s.pop@samsung.com>
 
        * doc/install.texi: Document supported versions of ISL.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 068cadf2332ada1280938d08a7b1f3936cefb09f..21512c6de574db3b3ec1eb2c9d500204b9987fc9 100644 (file)
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -25113,7 +25113,8 @@ ix86_expand_set_or_movmem (rtx dst, rtx src, rtx count_exp, rtx val_exp,
       dst = change_address (dst, BLKmode, destreg);
       set_mem_align (dst, desired_align * BITS_PER_UNIT);
       epilogue_size_needed = 0;
-      if (need_zero_guard && !min_size)
+      if (need_zero_guard
+         && min_size < (unsigned HOST_WIDE_INT) size_needed)
        {
          /* It is possible that we copied enough so the main loop will not
             execute.  */
@@ -25245,7 +25246,7 @@ ix86_expand_set_or_movmem (rtx dst, rtx src, rtx count_exp, rtx val_exp,
          max_size -= align_bytes;
        }
       if (need_zero_guard
-         && !min_size
+         && min_size < (unsigned HOST_WIDE_INT) size_needed
          && (count < (unsigned HOST_WIDE_INT) size_needed
              || (align_bytes == 0
                  && count < ((unsigned HOST_WIDE_INT) size_needed

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f832fb14e43419db21199c3857bf80f20fe79f7f..55e4cb03ff3c680e183480a3a0a99900835634d0 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-07-25  Uros Bizjak  <ubizjak@gmail.com>
+
+       PR target/66648
+       * gcc.target/i386/pr66648.c: New test.
+
 2015-07-25  Tom de Vries  <tom@codesourcery.com>
 
        * gcc.dg/graphite/graphite.exp: Include uns-*.c files in

diff --git a/gcc/testsuite/gcc.target/pr66648.c b/gcc/testsuite/gcc.target/pr66648.c
new file mode 100644 (file)
index 0000000..88c126f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/pr66648.c
@@ -0,0 +1,33 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -mstringop-strategy=unrolled_loop -mtune=nocona" } */
+
+#define PATTERN 0xdeadbeef
+#define SIZE    32
+
+struct S { int i; char str[SIZE]; int j; };
+
+void __attribute__((noclone, noinline))
+my_memcpy (char *, const char *, unsigned int);
+
+void
+my_memcpy (char *dst, const char *src, unsigned int len)
+{
+  if (len < 8)
+    __builtin_abort ();
+
+  __builtin_memcpy (dst, src, len);
+}
+
+int
+main (void)
+{
+  const char str[SIZE]= "1234567890123456789012345678901";
+  struct S *s = __builtin_malloc (sizeof (struct S));
+
+  s->j = PATTERN;
+  my_memcpy (s->str, str, SIZE);
+  if (s->j != PATTERN)
+    __builtin_abort ();
+
+  return 0;
+}