From: Eric Botcazou <ebotcazou@adacore.com>
Date: Wed, 16 Nov 2005 17:15:23 +0000 (+0000)
Subject: fold-const.c (const_binop): Don't constant fold the operation if the result has overf... 
X-Git-Tag: releases/gcc-4.1.0~753
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=68328cdaefaee1b9e218e08ff2955806ddd20403;p=thirdparty%2Fgcc.git

fold-const.c (const_binop): Don't constant fold the operation if the result has overflowed and...

	* fold-const.c (const_binop): Don't constant fold the operation
	if the result has overflowed and flag_trapping_math.
	* simplify-rtx.c (simplify_const_binary_operation): Likewise.

From-SVN: r107092
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0b14036d431b..8fb3e38e8be7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2005-11-16  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* fold-const.c (const_binop): Don't constant fold the operation
+	if the result has overflowed and flag_trapping_math.
+	* simplify-rtx.c (simplify_const_binary_operation): Likewise.
+
 2005-11-16  Daniel Jacobowitz  <dan@codesourcery.com>
 
 	* config/arm/unwind-arm.c (abort): Add prototype here.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 6f829adfa771..0e74391fe511 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -1537,6 +1537,16 @@ const_binop (enum tree_code code, tree arg1, tree arg2, int notrunc)
       inexact = real_arithmetic (&value, code, &d1, &d2);
       real_convert (&result, mode, &value);
 
+      /* Don't constant fold this floating point operation if
+	 the result has overflowed and flag_trapping_math.  */
+
+      if (flag_trapping_math
+	  && MODE_HAS_INFINITIES (mode)
+	  && REAL_VALUE_ISINF (result)
+	  && !REAL_VALUE_ISINF (d1)
+	  && !REAL_VALUE_ISINF (d2))
+	return NULL_TREE;
+
       /* Don't constant fold this floating point operation if the
 	 result may dependent upon the run-time rounding mode and
 	 flag_rounding_math is set, or if GCC's software emulation
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 44a1660e6882..657b2b59c23f 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -2242,6 +2242,17 @@ simplify_const_binary_operation (enum rtx_code code, enum machine_mode mode,
 				     &f0, &f1);
 	  real_convert (&result, mode, &value);
 
+	  /* Don't constant fold this floating point operation if
+	     the result has overflowed and flag_trapping_math.  */
+
+	  if (flag_trapping_math
+	      && MODE_HAS_INFINITIES (mode)
+	      && REAL_VALUE_ISINF (result)
+	      && !REAL_VALUE_ISINF (f0)
+	      && !REAL_VALUE_ISINF (f1))
+	    /* Overflow plus exception.  */
+	    return 0;
+
 	  /* Don't constant fold this floating point operation if the
 	     result may dependent upon the run-time rounding mode and
 	     flag_rounding_math is set, or if GCC's software emulation
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 22335ac22fc7..9c3f333ddd77 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2005-11-16  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.dg/fold-overflow-1.c: New test.
+
 2005-11-16  Daniel Jacobowitz  <dan@codesourcery.com>
 
 	* gcc.dg/cleanup-5.c, gcc.dg/cleanup-8.c, gcc.dg/cleanup-9.c,
diff --git a/gcc/testsuite/gcc.dg/fold-overflow-1.c b/gcc/testsuite/gcc.dg/fold-overflow-1.c
new file mode 100644
index 000000000000..2dd2188f8703
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-overflow-1.c
@@ -0,0 +1,18 @@
+/* { dg-compile } */
+/* { dg-options "-O -ftrapping-math" } */
+
+float f1 =  __FLT_MAX__ + __FLT_MAX__;
+
+float foo1(void)
+{
+  return  __FLT_MAX__ + __FLT_MAX__;
+}
+
+float f2 = 1.0f/0.0f;
+
+float foo2(void)
+{
+  return 1.0f/0.0f;
+}
+
+/* { dg-final { scan-assembler-times "2139095040" 2 } } */