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Re: [PATCH] Fix folding of logb (-Inf) (PR tree-optimization/57066)
- From: Marek Polacek <polacek at redhat dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 25 Apr 2013 17:24:48 +0200
- Subject: Re: [PATCH] Fix folding of logb (-Inf) (PR tree-optimization/57066)
- References: <20130425132350 dot GM13346 at redhat dot com> <CAFiYyc2jt-7thEySNnzRmcXLYUQt2_xu8rZnBxX4at71geMMHg at mail dot gmail dot com> <20130425151630 dot GO13346 at redhat dot com>
On Thu, Apr 25, 2013 at 05:16:31PM +0200, Marek Polacek wrote:
> Okay, patch updated. Ok now (which branches, all active?)?
> Regtested/bootstrapped again on x86_64-linux.
Eh, I've found a bug in previous version (not properly adjusted
testcase). So this one should be ok.
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 16:29:59.054615841 +0200
@@ -9698,7 +9698,16 @@ 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_VALUE_TYPE tem;
+ real_inf (&tem);
+ return build_real (rettype, tem);
+ }
+ 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 17:22:42.459765203 +0200
@@ -48,25 +48,25 @@ 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))) \
+ || 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)
#endif
@@ -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