Fix rintf rounding.

(cherry-picked from commit fe45ce09f366f2260aef528d37ae35070b3a2a36)

4 files changed, 92 insertions, 13 deletions

diff --git a/ChangeLog b/ChangeLog
index fea77729f2..86b074bdd5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,17 @@
 	manipulate bits before adding and subtracting TWO23[sx].
 	* math/libm-test.inc (nearbyint_test): Add more tests.
 
+2012-02-22  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #2548]
+	* sysdeps/ieee754/flt-32/s_rintf.c (__rintf): Do not manipulate
+	bits before adding and subtracting TWO23[sx].
+	* math/libm-test.inc (rint_test): Add more tests.
+	(rint_test_tonearest): Likewise.
+	(rint_test_towardzero): Likewise.
+	(rint_test_downward): Likewise.
+	(rint_test_upward: Likewise.
+
 2012-02-21  David S. Miller  <davem@davemloft.net>
 
 	* sysdeps/sparc/sparc32/fpu/libm-test-ulps: More jn test ULP updates.
diff --git a/NEWS b/NEWS
index 2b097a35de..a342ba8b14 100644
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,7 @@ Version 2.15.1
 
 * The following bugs are resolved with this release:
 
-  411, 2547, 11365, 13731, 13732, 13748
+  411, 2547, 2548, 11365, 13731, 13732, 13748
 
 Version 2.15
 
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 025a8eaae9..475857d8c2 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -5061,6 +5061,22 @@ rint_test (void)
   TEST_f_f (rint, 262142.75, 262143.0);
   TEST_f_f (rint, 524286.75, 524287.0);
   TEST_f_f (rint, 524288.75, 524289.0);
+  TEST_f_f (rint, 1048576.75, 1048577.0);
+  TEST_f_f (rint, 2097152.75, 2097153.0);
+  TEST_f_f (rint, -1048576.75, -1048577.0);
+  TEST_f_f (rint, -2097152.75, -2097153.0);
+#ifndef TEST_FLOAT
+  TEST_f_f (rint, 70368744177664.75, 70368744177665.0);
+  TEST_f_f (rint, 140737488355328.75, 140737488355329.0);
+  TEST_f_f (rint, 281474976710656.75, 281474976710657.0);
+  TEST_f_f (rint, 562949953421312.75, 562949953421313.0);
+  TEST_f_f (rint, 1125899906842624.75, 1125899906842625.0);
+  TEST_f_f (rint, -70368744177664.75, -70368744177665.0);
+  TEST_f_f (rint, -140737488355328.75, -140737488355329.0);
+  TEST_f_f (rint, -281474976710656.75, -281474976710657.0);
+  TEST_f_f (rint, -562949953421312.75, -562949953421313.0);
+  TEST_f_f (rint, -1125899906842624.75, -1125899906842625.0);
+#endif
 #ifdef TEST_LDOUBLE
   /* The result can only be represented in long double.  */
   TEST_f_f (rint, 4503599627370495.5L, 4503599627370496.0L);
@@ -5161,6 +5177,22 @@ rint_test_tonearest (void)
       TEST_f_f (rint, -0.1, -0.0);
       TEST_f_f (rint, -0.25, -0.0);
       TEST_f_f (rint, -0.625, -1.0);
+      TEST_f_f (rint, 1048576.75, 1048577.0);
+      TEST_f_f (rint, 2097152.75, 2097153.0);
+      TEST_f_f (rint, -1048576.75, -1048577.0);
+      TEST_f_f (rint, -2097152.75, -2097153.0);
+#ifndef TEST_FLOAT
+      TEST_f_f (rint, 70368744177664.75, 70368744177665.0);
+      TEST_f_f (rint, 140737488355328.75, 140737488355329.0);
+      TEST_f_f (rint, 281474976710656.75, 281474976710657.0);
+      TEST_f_f (rint, 562949953421312.75, 562949953421313.0);
+      TEST_f_f (rint, 1125899906842624.75, 1125899906842625.0);
+      TEST_f_f (rint, -70368744177664.75, -70368744177665.0);
+      TEST_f_f (rint, -140737488355328.75, -140737488355329.0);
+      TEST_f_f (rint, -281474976710656.75, -281474976710657.0);
+      TEST_f_f (rint, -562949953421312.75, -562949953421313.0);
+      TEST_f_f (rint, -1125899906842624.75, -1125899906842625.0);
+#endif
 #ifdef TEST_LDOUBLE
       /* The result can only be represented in long double.  */
       TEST_f_f (rint, 4503599627370495.5L, 4503599627370496.0L);
@@ -5231,6 +5263,22 @@ rint_test_towardzero (void)
       TEST_f_f (rint, -0.1, -0.0);
       TEST_f_f (rint, -0.25, -0.0);
       TEST_f_f (rint, -0.625, -0.0);
+      TEST_f_f (rint, 1048576.75, 1048576.0);
+      TEST_f_f (rint, 2097152.75, 2097152.0);
+      TEST_f_f (rint, -1048576.75, -1048576.0);
+      TEST_f_f (rint, -2097152.75, -2097152.0);
+#ifndef TEST_FLOAT
+      TEST_f_f (rint, 70368744177664.75, 70368744177664.0);
+      TEST_f_f (rint, 140737488355328.75, 140737488355328.0);
+      TEST_f_f (rint, 281474976710656.75, 281474976710656.0);
+      TEST_f_f (rint, 562949953421312.75, 562949953421312.0);
+      TEST_f_f (rint, 1125899906842624.75, 1125899906842624.0);
+      TEST_f_f (rint, -70368744177664.75, -70368744177664.0);
+      TEST_f_f (rint, -140737488355328.75, -140737488355328.0);
+      TEST_f_f (rint, -281474976710656.75, -281474976710656.0);
+      TEST_f_f (rint, -562949953421312.75, -562949953421312.0);
+      TEST_f_f (rint, -1125899906842624.75, -1125899906842624.0);
+#endif
 #ifdef TEST_LDOUBLE
       /* The result can only be represented in long double.  */
       TEST_f_f (rint, 4503599627370495.5L, 4503599627370495.0L);
@@ -5301,6 +5349,22 @@ rint_test_downward (void)
       TEST_f_f (rint, -0.1, -1.0);
       TEST_f_f (rint, -0.25, -1.0);
       TEST_f_f (rint, -0.625, -1.0);
+      TEST_f_f (rint, 1048576.75, 1048576.0);
+      TEST_f_f (rint, 2097152.75, 2097152.0);
+      TEST_f_f (rint, -1048576.75, -1048577.0);
+      TEST_f_f (rint, -2097152.75, -2097153.0);
+#ifndef TEST_FLOAT
+      TEST_f_f (rint, 70368744177664.75, 70368744177664.0);
+      TEST_f_f (rint, 140737488355328.75, 140737488355328.0);
+      TEST_f_f (rint, 281474976710656.75, 281474976710656.0);
+      TEST_f_f (rint, 562949953421312.75, 562949953421312.0);
+      TEST_f_f (rint, 1125899906842624.75, 1125899906842624.0);
+      TEST_f_f (rint, -70368744177664.75, -70368744177665.0);
+      TEST_f_f (rint, -140737488355328.75, -140737488355329.0);
+      TEST_f_f (rint, -281474976710656.75, -281474976710657.0);
+      TEST_f_f (rint, -562949953421312.75, -562949953421313.0);
+      TEST_f_f (rint, -1125899906842624.75, -1125899906842625.0);
+#endif
 #ifdef TEST_LDOUBLE
       /* The result can only be represented in long double.  */
       TEST_f_f (rint, 4503599627370495.5L, 4503599627370495.0L);
@@ -5371,6 +5435,22 @@ rint_test_upward (void)
       TEST_f_f (rint, -0.1, -0.0);
       TEST_f_f (rint, -0.25, -0.0);
       TEST_f_f (rint, -0.625, -0.0);
+      TEST_f_f (rint, 1048576.75, 1048577.0);
+      TEST_f_f (rint, 2097152.75, 2097153.0);
+      TEST_f_f (rint, -1048576.75, -1048576.0);
+      TEST_f_f (rint, -2097152.75, -2097152.0);
+#ifndef TEST_FLOAT
+      TEST_f_f (rint, 70368744177664.75, 70368744177665.0);
+      TEST_f_f (rint, 140737488355328.75, 140737488355329.0);
+      TEST_f_f (rint, 281474976710656.75, 281474976710657.0);
+      TEST_f_f (rint, 562949953421312.75, 562949953421313.0);
+      TEST_f_f (rint, 1125899906842624.75, 1125899906842625.0);
+      TEST_f_f (rint, -70368744177664.75, -70368744177664.0);
+      TEST_f_f (rint, -140737488355328.75, -140737488355328.0);
+      TEST_f_f (rint, -281474976710656.75, -281474976710656.0);
+      TEST_f_f (rint, -562949953421312.75, -562949953421312.0);
+      TEST_f_f (rint, -1125899906842624.75, -1125899906842624.0);
+#endif
 #ifdef TEST_LDOUBLE
       /* The result can only be represented in long double.  */
       TEST_f_f (rint, 4503599627370495.5L, 4503599627370496.0L);
diff --git a/sysdeps/ieee754/flt-32/s_rintf.c b/sysdeps/ieee754/flt-32/s_rintf.c
index 9ea9b6fc4f..9ba6b57d94 100644
--- a/sysdeps/ieee754/flt-32/s_rintf.c
+++ b/sysdeps/ieee754/flt-32/s_rintf.c
@@ -26,34 +26,22 @@ float
 __rintf(float x)
 {
 	int32_t i0,j0,sx;
-	u_int32_t i,i1;
 	float w,t;
 	GET_FLOAT_WORD(i0,x);
 	sx = (i0>>31)&1;
 	j0 = ((i0>>23)&0xff)-0x7f;
 	if(j0<23) {
 	    if(j0<0) {
-		if((i0&0x7fffffff)==0) return x;
-		i1 = (i0&0x07fffff);
-		i0 &= 0xfff00000;
-		i0 |= ((i1|-i1)>>9)&0x400000;
-		SET_FLOAT_WORD(x,i0);
 		w = TWO23[sx]+x;
 		t =  w-TWO23[sx];
 		GET_FLOAT_WORD(i0,t);
 		SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
 		return t;
-	    } else {
-		i = (0x007fffff)>>j0;
-		if((i0&i)==0) return x; /* x is integral */
-		i>>=1;
-		if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>j0);
 	    }
 	} else {
 	    if(j0==0x80) return x+x;	/* inf or NaN */
 	    else return x;		/* x is integral */
 	}
-	SET_FLOAT_WORD(x,i0);
 	w = TWO23[sx]+x;
 	return w-TWO23[sx];
 }