* fold-const.c (comparison_to_compcode): New function to convert

	an comparison TREE CODE into a bit-based representation.
	(compcode_to_comparison): New function to convert from this bit
	based representation back to a comparison TREE CODE.
	(fold_truthop): Simplify (x<y) && (x==y) and related composite
	comparisons.

	* gcc.c-tortuture/execute/compare-1.c: New test case.
	* gcc.c-tortuture/execute/compare-2.c: New test case.
	* gcc.c-tortuture/execute/compare-3.c: New test case.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@54647 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 229 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.c-torture/execute/compare-1.c b/gcc/testsuite/gcc.c-torture/execute/compare-1.c
new file mode 100644
index 00000000000..78b465024ea
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/compare-1.c
@@ -0,0 +1,119 @@
+/* Copyright (C) 2002 Free Software Foundation.
+
+   Test for correctness of composite comparisons.
+
+   Written by Roger Sayle, 3rd June 2002.  */
+
+extern void abort (void);
+
+int ieq (int x, int y, int ok)
+{
+  if ((x<=y) && (x>=y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+
+  if ((x<=y) && (x==y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+
+  if ((x<=y) && (y<=x))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+
+  if ((y==x) && (x<=y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+}
+
+int ine (int x, int y, int ok)
+{
+  if ((x<y) || (x>y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+}
+
+int ilt (int x, int y, int ok)
+{
+  if ((x<y) && (x!=y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+}
+
+int ile (int x, int y, int ok)
+{
+  if ((x<y) || (x==y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+}
+
+int igt (int x, int y, int ok)
+{
+  if ((x>y) && (x!=y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+}
+
+int ige (int x, int y, int ok)
+{
+  if ((x>y) || (x==y))
+    {
+      if (!ok) abort ();
+    }
+  else
+    if (ok) abort ();
+}
+
+int
+main ()
+{
+  ieq (1, 4, 0);
+  ieq (3, 3, 1);
+  ieq (5, 2, 0);
+
+  ine (1, 4, 1);
+  ine (3, 3, 0);
+  ine (5, 2, 1);
+
+  ilt (1, 4, 1);
+  ilt (3, 3, 0);
+  ilt (5, 2, 0);
+
+  ile (1, 4, 1);
+  ile (3, 3, 1);
+  ile (5, 2, 0);
+
+  igt (1, 4, 0);
+  igt (3, 3, 0);
+  igt (5, 2, 1);
+
+  ige (1, 4, 0);
+  ige (3, 3, 1);
+  ige (5, 2, 1);
+
+  return 0;
+}
+
diff --git a/gcc/testsuite/gcc.c-torture/execute/compare-2.c b/gcc/testsuite/gcc.c-torture/execute/compare-2.c
new file mode 100644
index 00000000000..858df294eca
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/compare-2.c
@@ -0,0 +1,24 @@
+/* Copyright (C) 2002 Free Software Foundation.
+
+   Ensure that the composite comparison optimization doesn't misfire
+   and attempt to combine a signed comparison with an unsigned one.
+
+   Written by Roger Sayle, 3rd June 2002.  */
+
+extern void abort (void);
+
+int
+foo (int x, int y)
+{
+  /* If miscompiled the following may become "x == y".  */
+  return (x<=y) && ((unsigned int)x >= (unsigned int)y);
+}
+
+int
+main ()
+{
+  if (! foo (-1,0))
+    abort ();
+  return 0;
+}
+
diff --git a/gcc/testsuite/gcc.c-torture/execute/compare-3.c b/gcc/testsuite/gcc.c-torture/execute/compare-3.c
new file mode 100644
index 00000000000..6549c904b52
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/compare-3.c
@@ -0,0 +1,86 @@
+/* Copyright (C) 2002 Free Software Foundation.
+
+   Test for composite comparison always true/false optimization.
+
+   Written by Roger Sayle, 7th June 2002.  */
+
+extern void link_error0 ();
+extern void link_error1 ();
+
+void
+test1 (int x, int y)
+{
+  if ((x==y) && (x!=y))
+    link_error0();
+}
+
+void
+test2 (int x, int y)
+{
+  if ((x<y) && (x>y))
+    link_error0();
+}
+
+void
+test3 (int x, int y)
+{
+  if ((x<y) && (y<x))
+    link_error0();
+}
+
+void 
+test4 (int x, int y)
+{
+  if ((x==y) || (x!=y))
+    {
+    }
+  else
+    link_error1 ();
+}
+
+void
+test5 (int x, int y)
+{
+  if ((x>=y) || (x<y))
+    {
+    }
+  else
+    link_error1 ();
+}
+
+void
+test6 (int x, int y)
+{
+  if ((x<=y) || (y<x))
+    {
+    }
+  else
+    link_error1 ();
+}
+
+void
+all_tests (int x, int y)
+{
+  test1 (x, y);
+  test2 (x, y);
+  test3 (x, y);
+  test4 (x, y);
+  test5 (x, y);
+  test6 (x, y);
+}
+
+int
+main ()
+{
+  all_tests (0, 0);
+  all_tests (1, 2);
+  all_tests (4, 3);
+
+  return 0;
+}
+
+#ifndef __OPTIMIZE__
+void link_error0() {}
+void link_error1() {}
+#endif /* ! __OPTIMIZE__ */
+