2006-12-08  Jakub Jelinek  <jakub@redhat.com>

	* g++.dg/opt/ifcvt1.C: New test.

2005-11-09  Eric Botcazou  <ebotcazou@adacore.com>

	* ifcvt.c (noce_get_alt_condition): Use prev_nonnote_insn.

	(noce_try_abs): Negate if the comparison is reversed.

	Look only one instruction backwards for a REG_EQUAL note.

	* gcc.dg/ifcvt-fabs-1.c: New test.

--- gcc/ifcvt.c.orig	2005-11-21 11:43:21.000000000 -0200

+++ gcc/ifcvt.c	2006-10-26 02:21:07.000000000 -0300

@@ -1406,7 +1406,7 @@ noce_get_alt_condition (struct noce_if_i

       rtx prev_insn;

       /* First, look to see if we put a constant in a register.  */

-      prev_insn = PREV_INSN (if_info->cond_earliest);

+      prev_insn = prev_nonnote_insn (if_info->cond_earliest);

       if (prev_insn

 	  && INSN_P (prev_insn)

 	  && GET_CODE (PATTERN (prev_insn)) == SET)

@@ -1642,25 +1642,30 @@ noce_try_abs (struct noce_if_info *if_in

   if (rtx_equal_p (XEXP (cond, 0), b))

     c = XEXP (cond, 1);

   else if (rtx_equal_p (XEXP (cond, 1), b))

-    c = XEXP (cond, 0);

+    {

+      c = XEXP (cond, 0);

+      negate = !negate;

+    }

   else

     return FALSE;

-  /* Verify that C is zero.  Search backward through the block for

-     a REG_EQUAL note if necessary.  */

+  /* Verify that C is zero.  Search one step backward for a

+     REG_EQUAL note or a simple source if necessary.  */

   if (REG_P (c))

     {

-      rtx insn, note = NULL;

-      for (insn = earliest;

-	   insn != BB_HEAD (if_info->test_bb);

-	   insn = PREV_INSN (insn))

-	if (INSN_P (insn)

-	    && ((note = find_reg_note (insn, REG_EQUAL, c))

-		|| (note = find_reg_note (insn, REG_EQUIV, c))))

-	  break;

-      if (! note)

+      rtx set, insn = prev_nonnote_insn (earliest);

+      if (insn

+	  && (set = single_set (insn))

+	  && rtx_equal_p (SET_DEST (set), c))

+	{

+	  rtx note = find_reg_equal_equiv_note (insn);

+	  if (note)

+	    c = XEXP (note, 0);

+	  else

+	    c = SET_SRC (set);

+	}

+      else

 	return FALSE;

-      c = XEXP (note, 0);

     }

   if (GET_CODE (c) == MEM

       && GET_CODE (XEXP (c, 0)) == SYMBOL_REF

--- gcc/testsuite/gcc.dg/ifcvt-fabs-1.c	1970-01-01 00:00:00.000000000 +0000

+++ gcc/testsuite/gcc.dg/ifcvt-fabs-1.c	2006-10-26 02:20:24.000000000 -0300

@@ -0,0 +1,21 @@

+/* { dg-do run } */

+/* { dg-options "-O" } */

+/* { dg-options "-O -march=i686" { target i686-*-* } } */

+

+extern void abort(void);

+

+float foo(float f)

+{

+  if (f < 0.0f)

+    f = -f;

+

+  return f;

+}

+

+int main(void)

+{

+  if (foo (-1.0f) != 1.0f)

+    abort ();

+

+  return 0;

+}

--- gcc/testsuite/g++.dg/opt/ifcvt1.C	2006-10-04 16:28:56.502613000 +0200

+++ gcc/testsuite/g++.dg/opt/ifcvt1.C	2006-12-08 12:23:23.000000000 +0100

@@ -0,0 +1,17 @@

+// { dg-do compile }

+// { dg-options "-O2 -fnon-call-exceptions" }

+

+struct S { ~S () throw () {} };

+double bar ();

+

+int

+foo ()

+{

+  S a;

+  int i = 0;

+  double c = bar ();

+  c = c < 0 ? -c : c;

+  if (c <= 1.e-8)

+    i += 24;

+  return i;

+}