poly_int: expand_ifn_atomic_compare_exchange_into_call

This patch makes the mode size assumptions in
expand_ifn_atomic_compare_exchange_into_call a bit more
explicit, so that a later patch can add a to_constant () call.

2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* builtins.c (expand_ifn_atomic_compare_exchange_into_call): Assert
	that the mode size is in the set {1, 2, 4, 8, 16}.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r256157

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fb3d07de0a1199633673d3912f181d91ddb517e2..2eea29ba5e0a349f7e665b52a6d64e0022afbd23 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
+           Alan Hayward  <alan.hayward@arm.com>
+           David Sherwood  <david.sherwood@arm.com>
+
+       * builtins.c (expand_ifn_atomic_compare_exchange_into_call): Assert
+       that the mode size is in the set {1, 2, 4, 8, 16}.
+
 2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
            Alan Hayward  <alan.hayward@arm.com>
            David Sherwood  <david.sherwood@arm.com>

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 98eb804a2753a26c1e8f50f1745a2f665870e346..c5d8435f2513b7894408c055ecb84692ff2a5329 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -5990,9 +5990,12 @@ expand_ifn_atomic_compare_exchange_into_call (gcall *call, machine_mode mode)
   /* Skip the boolean weak parameter.  */
   for (z = 4; z < 6; z++)
     vec->quick_push (gimple_call_arg (call, z));
+  /* At present we only have BUILT_IN_ATOMIC_COMPARE_EXCHANGE_{1,2,4,8,16}.  */
+  unsigned int bytes_log2 = exact_log2 (GET_MODE_SIZE (mode));
+  gcc_assert (bytes_log2 < 5);
   built_in_function fncode
     = (built_in_function) ((int) BUILT_IN_ATOMIC_COMPARE_EXCHANGE_1
-                          + exact_log2 (GET_MODE_SIZE (mode)));
+                          + bytes_log2);
   tree fndecl = builtin_decl_explicit (fncode);
   tree fn = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (fndecl)),
                    fndecl);