From 0b5b178caea0417ff23d0609b1416e3f3e4f6689 Mon Sep 17 00:00:00 2001
From: Jan Hubicka <hubicka@ucw.cz>
Date: Mon, 22 Jul 2024 18:01:57 +0200
Subject: 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.
---
 gcc/ipa-icf-gimple.cc                          |  4 ++++
 gcc/testsuite/gcc.c-torture/compile/pr115277.c | 28 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr115277.c

(limited to 'gcc')

diff --git a/gcc/ipa-icf-gimple.cc b/gcc/ipa-icf-gimple.cc
index c25eb24..4c3174b 100644
--- 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
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;
+}
-- 
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