re PR target/65730 (xtensa: ICE in libstdc++-v3/include/bits/atomic_base.h: In…

re PR target/65730 (xtensa: ICE in libstdc++-v3/include/bits/atomic_base.h: In function ‘bool std::atomic_flag_test_and_set_explicit(std::__atomic_flag_base*, std::memory_order)’)

Fix PR target/65730

2015-05-20  Max Filippov  <jcmvbkbc@gmail.com>
gcc/
	* config/xtensa/xtensa.c (init_alignment_context): Replace MULT
	by BITS_PER_UNIT with ASHIFT by exact_log2 (BITS_PER_UNIT).

From-SVN: r223452

gcc/ChangeLog

+2015-05-20  Max Filippov  <jcmvbkbc@gmail.com>
+
+	* config/xtensa/xtensa.c (init_alignment_context): Replace MULT
+	by BITS_PER_UNIT with ASHIFT by exact_log2 (BITS_PER_UNIT).
+
 2015-05-20  Jeff Law  <law@redhat.com>
 
 	* tree-ssa-threadupdate.c (mark_threaded_blocks): Properly

gcc/config/xtensa/xtensa.c

@@ -1461,8 +1461,9 @@ init_alignment_context (struct alignment_context *ac, rtx mem)
   if (ac->shift != NULL_RTX)
     {
       /* Shift is the byte count, but we need the bitcount.  */
-      ac->shift = expand_simple_binop (SImode, MULT, ac->shift,
-				       GEN_INT (BITS_PER_UNIT),
+      gcc_assert (exact_log2 (BITS_PER_UNIT) >= 0);
+      ac->shift = expand_simple_binop (SImode, ASHIFT, ac->shift,
+				       GEN_INT (exact_log2 (BITS_PER_UNIT)),
 				       NULL_RTX, 1, OPTAB_DIRECT);
       ac->modemask = expand_simple_binop (SImode, ASHIFT,
 					  GEN_INT (GET_MODE_MASK (mode)),