From: Roger Sayle <roger@eyesopen.com>
Date: Thu, 16 Mar 2006 16:34:05 +0000 (+0000)
Subject: re PR middle-end/21781 (real.c incorrectly values zero with a large exponent)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a47564c87c482e932230f440463c9c1a962e66d8;p=gcc.git

re PR middle-end/21781 (real.c incorrectly values zero with a large exponent)


	PR middle-end/21781
	* real.c (real_from_string): If the mantissa is zero, don't bother
	parsing the exponent as the result should always be zero.

	* gcc.dg/real-const-1.c: New test case.

From-SVN: r112136
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b7870e32cdd..3dac824d2d9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-03-16  Roger Sayle  <roger@eyesopen.com>
+
+	PR middle-end/21781
+	* real.c (real_from_string): If the mantissa is zero, don't bother
+	parsing the exponent as the result should always be zero.
+
 2006-03-16  Andreas Krebbel  <krebbel1@de.ibm.com>
 
 	* simplify-rtx.c (simplify_plus_minus): Simplify within CONST terms.
diff --git a/gcc/real.c b/gcc/real.c
index c4b6479067f..1e1083f9abe 100644
--- a/gcc/real.c
+++ b/gcc/real.c
@@ -1862,6 +1862,11 @@ real_from_string (REAL_VALUE_TYPE *r, const char *str)
 	      str++;
 	    }
 	}
+
+      /* If the mantissa is zero, ignore the exponent.  */
+      if (!cmp_significand_0 (r))
+	goto underflow;
+
       if (*str == 'p' || *str == 'P')
 	{
 	  bool exp_neg = false;
@@ -1934,6 +1939,10 @@ real_from_string (REAL_VALUE_TYPE *r, const char *str)
 	    }
 	}
 
+      /* If the mantissa is zero, ignore the exponent.  */
+      if (r->cl == rvc_zero)
+	goto underflow;
+
       if (*str == 'e' || *str == 'E')
 	{
 	  bool exp_neg = false;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6b093acf92e..90dc7004ae1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2006-03-16  Roger Sayle  <roger@eyesopen.com>
+
+	PR middle-end/21781
+	* gcc.dg/real-const-1.c: New test case.
+
 2006-03-15  Geoffrey Keating  <geoffk@apple.com>
 
 	* g++.old-deja/g++.other/init18.C: New.
diff --git a/gcc/testsuite/gcc.dg/real-const-1.c b/gcc/testsuite/gcc.dg/real-const-1.c
new file mode 100644
index 00000000000..3e2bbfde8fc
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/real-const-1.c
@@ -0,0 +1,4 @@
+/* PR middle-end/21781.  */
+/* { dg-do compile } */
+
+int f[.0e200000000 == 0?1:-1];