This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
[PATCH] Fix folding of logb (-Inf) (PR tree-optimization/57066)
- From: Marek Polacek <polacek at redhat dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 25 Apr 2013 15:23:50 +0200
- Subject: [PATCH] Fix folding of logb (-Inf) (PR tree-optimization/57066)
This is an attempt to fix PR57066, where when folding logb call,
we returned -Inf for logb(-Inf), which is not correct.
I had to adjust one testcase, because it checked for a wrong value.
What I don't know yet is what we should return for -Nan, it should be
in C9X standard, but I don't have it by hand.
Does this look sane? So far regtested/bootstrapped on x86_64-linux.
2013-04-25 Marek Polacek <polacek@redhat.com>
* builtins.c (fold_builtin_logb): Return +Inf for -Inf.
* gcc.dg/torture/builtin-logb-1.c: Adjust testcase.
--- gcc/builtins.c.mp 2013-04-25 12:52:37.463451032 +0200
+++ gcc/builtins.c 2013-04-25 14:26:33.963099851 +0200
@@ -9698,7 +9698,12 @@ fold_builtin_logb (location_t loc, tree
case rvc_inf:
/* If arg is Inf or NaN and we're logb, return it. */
if (TREE_CODE (rettype) == REAL_TYPE)
- return fold_convert_loc (loc, rettype, arg);
+ {
+ /* For logb(-Inf) we have to return +Inf. */
+ if (value->cl == rvc_inf && !tree_expr_nonnegative_p (arg))
+ real_inf (TREE_REAL_CST_PTR (arg));
+ return fold_convert_loc (loc, rettype, arg);
+ }
/* Fall through... */
case rvc_zero:
/* Zero may set errno and/or raise an exception for logb, also
--- gcc/testsuite/gcc.dg/torture/builtin-logb-1.c.mp 2013-04-25 13:23:18.408224450 +0200
+++ gcc/testsuite/gcc.dg/torture/builtin-logb-1.c 2013-04-25 14:28:48.900534671 +0200
@@ -48,19 +48,19 @@ extern void link_error(int);
/* Test if FUNCRES(FUNC(NEG FUNCARG(ARGARG))) is false. Check the
sign as well. */
#ifndef __SPU__
-#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES) do { \
+#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES,NEG2) do { \
if (!__builtin_##FUNCRES##f(__builtin_##FUNC(NEG __builtin_##FUNCARG##f(ARGARG))) \
- || CKSGN_F(__builtin_##FUNC##f(NEG __builtin_##FUNCARG##f(ARGARG)), NEG __builtin_##FUNCARG##f(ARGARG))) \
+ || CKSGN_F(__builtin_##FUNC##f(NEG __builtin_##FUNCARG##f(ARGARG)), NEG2 __builtin_##FUNCARG##f(ARGARG))) \
link_error(__LINE__); \
if (!__builtin_##FUNCRES(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG))) \
- || CKSGN(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG)), NEG __builtin_##FUNCARG(ARGARG))) \
+ || CKSGN(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG)), NEG2 __builtin_##FUNCARG(ARGARG))) \
link_error(__LINE__); \
if (!__builtin_##FUNCRES##l(__builtin_##FUNC##l(NEG __builtin_##FUNCARG##l(ARGARG))) \
- || CKSGN_L(__builtin_##FUNC##l(NEG __builtin_##FUNCARG##l(ARGARG)), NEG __builtin_##FUNCARG##l(ARGARG))) \
+ || CKSGN_L(__builtin_##FUNC##l(NEG __builtin_##FUNCARG##l(ARGARG)), NEG2 __builtin_##FUNCARG##l(ARGARG))) \
link_error(__LINE__); \
} while (0)
#else
-#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES) do { \
+#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES,NEG2) do { \
/* SPU single-precision floating point format does not support Inf or Nan. */ \
if (!__builtin_##FUNCRES(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG))) \
|| CKSGN(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG)), NEG __builtin_##FUNCARG(ARGARG))) \
@@ -173,15 +173,15 @@ foo(void)
/* Test for f(+-Inf) -> +-Inf and f(+-NaN) -> +-NaN, regardless of
the radix. */
- TESTIT3 (logb, ,inf, , isinf);
- TESTIT3 (logb, - ,inf, , isinf);
- TESTIT3 (logb, ,nan, "", isnan);
- TESTIT3 (logb, - ,nan, "", isnan);
-
- TESTIT3 (significand, ,inf, , isinf);
- TESTIT3 (significand, - ,inf, , isinf);
- TESTIT3 (significand, ,nan, "", isnan);
- TESTIT3 (significand, - ,nan, "", isnan);
+ TESTIT3 (logb, ,inf, , isinf, );
+ TESTIT3 (logb, - ,inf, , isinf, );
+ TESTIT3 (logb, ,nan, "", isnan, );
+ TESTIT3 (logb, - ,nan, "", isnan, -);
+
+ TESTIT3 (significand, ,inf, , isinf, );
+ TESTIT3 (significand, - ,inf, , isinf, -);
+ TESTIT3 (significand, ,nan, "", isnan, );
+ TESTIT3 (significand, - ,nan, "", isnan, -);
}
int main()
Marek