Compare loop bounds in ipa-icf

Hi,
this testcase shows another poblem with missing comparators for metadata
in ICF. With value ranges available to loop optimizations during early
opts we can estimate number of iterations based on guarding condition that
can be split away by the fnsplit pass. This patch disables ICF when
number of iteraitons does not match.

Bootstrapped/regtesed x86_64-linux, will commit it shortly

gcc/ChangeLog:

	PR ipa/115277
	* ipa-icf-gimple.cc (func_checker::compare_loops): compare loop
	bounds.

gcc/testsuite/ChangeLog:

	* gcc.c-torture/compile/pr115277.c: New test.

diff --git a/gcc/ipa-icf-gimple.cc b/gcc/ipa-icf-gimple.cc
index c25eb24710f6a785d2c739e5d5ad7c066c3e0f3d..4c3174b68b67bfa2788a607aa461db3eefa71871 100644 (file)
--- a/gcc/ipa-icf-gimple.cc
+++ b/gcc/ipa-icf-gimple.cc
@@ -543,6 +543,10 @@ func_checker::compare_loops (basic_block bb1, basic_block bb2)
     return return_false_with_msg ("unroll");
   if (!compare_variable_decl (l1->simduid, l2->simduid))
     return return_false_with_msg ("simduid");
+  if ((l1->any_upper_bound != l2->any_upper_bound)
+      || (l1->any_upper_bound
+         && (l1->nb_iterations_upper_bound != l2->nb_iterations_upper_bound)))
+    return return_false_with_msg ("nb_iterations_upper_bound");
 
   return true;
 }

diff --git a/gcc/testsuite/gcc.c-torture/compile/pr115277.c b/gcc/testsuite/gcc.c-torture/compile/pr115277.c
new file mode 100644 (file)
index 0000000..27449eb
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr115277.c
@@ -0,0 +1,28 @@
+int array[1000];
+void
+test (int a)
+{
+        if (__builtin_expect (a > 3, 1))
+                return;
+        for (int i = 0; i < a; i++)
+                array[i]=i;
+}
+void
+test2 (int a)
+{
+        if (__builtin_expect (a > 10, 1))
+                return;
+        for (int i = 0; i < a; i++)
+                array[i]=i;
+}
+int
+main()
+{
+        test(1);
+        test(2);
+        test(3);
+        test2(10);
+        if (array[9] != 9)
+                __builtin_abort ();
+        return 0;
+}