re PR rtl-optimization/68636 (unnecessary unaligned load on mips o32)

2015-12-04  Richard Biener  <rguenther@suse.de>

	PR middle-end/68636
	* builtins.c (get_pointer_alignment_1): Take care of byte to
	bit alignment computation overflow.

From-SVN: r231246

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0a3fd7939dd5496e6e6b83c517efe87992c63184..fc026c58ee7ad7518611436b2e9cc1fa20dc6e2f 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-12-04  Richard Biener  <rguenther@suse.de>
+
+       PR middle-end/68636
+       * builtins.c (get_pointer_alignment_1): Take care of byte to
+       bit alignment computation overflow.
+
 2015-12-04  Richard Biener  <rguenther@suse.de>
 
        PR middle-end/67438

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 7c614e6336edf4c10646d26a94c21c66e5bf1b29..9d816044c73ffebcd8359b004648f0c16ac2b434 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -458,6 +458,10 @@ get_pointer_alignment_1 (tree exp, unsigned int *alignp,
        {
          *bitposp = ptr_misalign * BITS_PER_UNIT;
          *alignp = ptr_align * BITS_PER_UNIT;
+         /* Make sure to return a sensible alignment when the multiplication
+            by BITS_PER_UNIT overflowed.  */
+         if (*alignp == 0)
+           *alignp = 1u << (HOST_BITS_PER_INT - 1);
          /* We cannot really tell whether this result is an approximation.  */
          return true;
        }