re PR middle-end/36578 (cast to long double not taken into account when result stored to a double)

	PR middle-end/36578
	* convert.c (convert_to_real): Do not optimize conversions of
	binary arithmetic operations between binary and decimal
	floating-point types.  Consider mode of target type in determining
	decimal type for arithmetic.  Unless
	flag_unsafe_math_optimizations, do not optimize binary conversions
	where this may change rounding behavior.
	* real.c (real_can_shorten_arithmetic): New.
	* real.h (real_can_shorten_arithmetic): Declare.

testsuite:
	* gcc.dg/dfp/convert-bfp-13.c, gcc.dg/dfp/convert-bfp-14.c,
	gcc.dg/dfp/convert-dfp-fold-2.c, gcc.target/i386/pr36578-1.c,
	gcc.target/i386/pr36578-2.c: New tests.

From-SVN: r141432

6 files changed, 106 insertions, 0 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0708401..6e3f6f2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2008-10-29  Joseph Myers  <joseph@codesourcery.com>
+
+	PR middle-end/36578
+	* gcc.dg/dfp/convert-bfp-13.c, gcc.dg/dfp/convert-bfp-14.c,
+	gcc.dg/dfp/convert-dfp-fold-2.c, gcc.target/i386/pr36578-1.c,
+	gcc.target/i386/pr36578-2.c: New tests.
+
 2008-10-29  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/37870
diff --git a/gcc/testsuite/gcc.dg/dfp/convert-bfp-13.c b/gcc/testsuite/gcc.dg/dfp/convert-bfp-13.c
new file mode 100644
index 0000000..91a5b49
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/convert-bfp-13.c
@@ -0,0 +1,20 @@
+/* Test for bug where fold changed binary operation to decimal
+   depending on typedefs.  */
+/* { dg-options "-std=gnu99" } */
+
+extern void abort (void);
+extern void exit (int);
+
+volatile double d = 1.2345675;
+
+typedef const volatile _Decimal32 d32;
+
+int
+main (void)
+{
+  _Decimal32 a = (d * d);
+  d32 b = (d * d);
+  if (a != b)
+    abort ();
+  exit (0);
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/convert-bfp-14.c b/gcc/testsuite/gcc.dg/dfp/convert-bfp-14.c
new file mode 100644
index 0000000..a1312d2a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/convert-bfp-14.c
@@ -0,0 +1,17 @@
+/* Test for bug where fold narrowed decimal floating-point
+   operations.  */
+/* { dg-options "-std=gnu99" } */
+
+extern void abort (void);
+extern void exit (int);
+
+volatile _Decimal32 f = 1.23456DF;
+volatile _Decimal64 d = 1.23456DD;
+
+int
+main (void)
+{
+  if ((double)((_Decimal64)f * (_Decimal64)f) != (double)(d * d))
+    abort ();
+  exit (0);
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/convert-dfp-fold-2.c b/gcc/testsuite/gcc.dg/dfp/convert-dfp-fold-2.c
new file mode 100644
index 0000000..9f09279
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/convert-dfp-fold-2.c
@@ -0,0 +1,17 @@
+/* Test for bug where fold narrowed decimal floating-point
+   operations.  */
+/* { dg-options "-std=gnu99" } */
+
+extern void abort (void);
+extern void exit (int);
+
+volatile _Decimal32 f = 1.23456DF;
+volatile _Decimal64 d = 1.23456DD;
+
+int
+main (void)
+{
+  if ((_Decimal128)((_Decimal64)f * (_Decimal64)f) != (_Decimal128)(d * d))
+    abort ();
+  exit (0);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr36578-1.c b/gcc/testsuite/gcc.target/i386/pr36578-1.c
new file mode 100644
index 0000000..cae0d70
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr36578-1.c
@@ -0,0 +1,22 @@
+/* Test for unsafe floating-point conversions.  PR 36578.  */
+/* { dg-do run } */
+/* { dg-options "-msse2 -mfpmath=sse" } */
+
+#include "sse2-check.h"
+
+extern void abort (void);
+extern void exit (int);
+extern int printf(const char *, ...);
+
+volatile double d1 = 1.0;
+volatile double d2 = 0x1.00001p-53;
+volatile double d3;
+
+static void
+sse2_test (void)
+{
+  d3 = (double)((long double)d1 + (long double)d2);
+  if (d3 != d1)
+    abort ();
+  exit (0);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr36578-2.c b/gcc/testsuite/gcc.target/i386/pr36578-2.c
new file mode 100644
index 0000000..19143cf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr36578-2.c
@@ -0,0 +1,23 @@
+/* Test for unsafe floating-point conversions.  */
+/* { dg-do run } */
+/* { dg-options "-msse2 -mfpmath=sse" } */
+
+#include "sse2-check.h"
+
+extern void abort (void);
+extern void exit (int);
+extern int printf(const char *, ...);
+
+volatile double d1 = 0x1.000001p0;
+volatile double d2 = 0x1p-54;
+volatile float f = 0x1.000002p0f;
+volatile float f2;
+
+static void
+sse2_test (void)
+{
+  f2 = (float)((long double)d1 + (long double)d2);
+  if (f != f2)
+    abort ();
+  exit (0);
+}