simplify-rtx.c (simplify_relational_operation): Optimize abs(x) < 0.0 (and…

simplify-rtx.c (simplify_relational_operation): Optimize abs(x) < 0.0 (and abs(x) >= 0.0 when using -ffast-math).


	* simplify-rtx.c (simplify_relational_operation): Optimize
	abs(x) < 0.0 (and abs(x) >= 0.0 when using -ffast-math).

	* gcc.c-torture/execute/20020720-1.c: New test case.

From-SVN: r55614

gcc/ChangeLog

+2002-07-20  Roger Sayle  <roger@eyesopen.com>
+
+	* simplify-rtx.c (simplify_relational_operation): Optimize
+	abs(x) < 0.0 (and abs(x) >= 0.0 when using -ffast-math).
+
 2002-07-20  Michae Matz  <matz@suse.de>
 
 	* ra-build.c: (remember_web_was_spilled): Use GENERAL_REGS.

gcc/simplify-rtx.c

@@ -2075,6 +2075,28 @@ simplify_relational_operation (code, mode, op0, op1)
 	    return const0_rtx;
 	  break;
 
+	case LT:
+	  /* Optimize abs(x) < 0.0.  */
+	  if (trueop1 == CONST0_RTX (mode))
+	    {
+	      tem = GET_CODE (trueop0) == FLOAT_EXTEND ? XEXP (trueop0, 0)
+						       : trueop0;
+	      if (GET_CODE (tem) == ABS)
+		return const0_rtx;
+	    }
+	  break;
+
+	case GE:
+	  /* Optimize abs(x) >= 0.0.  */
+	  if (trueop1 == CONST0_RTX (mode) && !HONOR_NANS (mode))
+	    {
+	      tem = GET_CODE (trueop0) == FLOAT_EXTEND ? XEXP (trueop0, 0)
+						       : trueop0;
+	      if (GET_CODE (tem) == ABS)
+		return const1_rtx;
+	    }
+	  break;
+
 	default:
 	  break;
 	}

gcc/testsuite/ChangeLog

+2002-07-20  Roger Sayle  <roger@eyesopen.com>
+
+	* gcc.c-torture/execute/20020720-1.c: New testcase.
+
 2002-07-20  Neil Booth  <neil@daikokuya.co.uk>
 
 	* gcc.dg/cpp/Wsignprom.c: New tests.

gcc/testsuite/gcc.c-torture/execute/20020720-1.c

+/* Copyright (C) 2002  Free Software Foundation.
+
+   Ensure that fabs(x) < 0.0 optimization is working.
+
+   Written by Roger Sayle, 20th July 2002.  */
+
+extern void abort (void);
+extern double fabs (double);
+extern void link_error (void);
+
+void
+foo (double x)
+{
+  double p, q;
+
+  p = fabs (x);
+  q = 0.0;
+  if (p < q)
+    link_error ();
+}
+
+int
+main()
+{
+  foo (1.0);
+  return 0;
+}
+
+#ifndef __OPTIMIZE__
+void
+link_error ()
+{
+  abort ();
+}
+#endif
+