HJ's regression tester shows the new test gcc.dg/iec-559-macros-9.c
failing for 32-bit x86. It turns out the excess precision handling
for determining the value of __GCC_IEC_559 has two problems:
flag_excess_precision hasn't been initialized at the point it's
tested, so flag_excess_precision_cmdline (which *has* been updated
based on flag_iso) needs testing instead, and on x86 with standard
excess precision enabled there is no adddf3 pattern (because all x87
arithmetic is in XFmode) so the default hook wrongly thinks it's a
soft-float target. This can be fixed by adding an x86-specific hook
implementation; the issue doesn't affect any other target defining
TARGET_FLT_EVAL_METHOD, because only x86 makes sure to disable the
problematic insn patterns for -fexcess-precision=standard.
Bootstrapped with no regressions on x86_64-unknown-linux-gnu. OK to
commit (the x86 target hook addition)?
2013-11-05 Joseph Myers <jos...@codesourcery.com>
* config/i386/i386.c (ix86_float_exceptions_rounding_supported_p):
New function.
(TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P): Define.
c-family:
2013-11-05 Joseph Myers <jos...@codesourcery.com>
* c-cppbuiltin.c (cpp_iec_559_value): Test
flag_excess_precision_cmdline not flag_excess_precision.
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c (revision 204351)
+++ gcc/config/i386/i386.c (working copy)
@@ -43375,6 +43375,18 @@ ix86_memmodel_check (unsigned HOST_WIDE_INT val)
return val;
}
+/* Implement TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P. */
+
+static bool
+ix86_float_exceptions_rounding_supported_p (void)
+{
+ /* For x87 floating point with standard excess precision handling,
+ there is no adddf3 pattern (since x87 floating point only has
+ XFmode operations) so the default hook implementation gets this
+ wrong. */
+ return TARGET_80387 || TARGET_SSE_MATH;
+}
+
/* Initialize the GCC target structure. */
#undef TARGET_RETURN_IN_MEMORY
#define TARGET_RETURN_IN_MEMORY ix86_return_in_memory
@@ -43747,6 +43759,10 @@ ix86_memmodel_check (unsigned HOST_WIDE_INT val)
#undef TARGET_SPILL_CLASS
#define TARGET_SPILL_CLASS ix86_spill_class
+#undef TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P
+#define TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P \
+ ix86_float_exceptions_rounding_supported_p
+
struct gcc_target targetm = TARGET_INITIALIZER;
#include "gt-i386.h"
Index: gcc/c-family/c-cppbuiltin.c
===================================================================
--- gcc/c-family/c-cppbuiltin.c (revision 204351)
+++ gcc/c-family/c-cppbuiltin.c (working copy)
@@ -734,7 +734,7 @@ cpp_iec_559_value (void)
if (flag_iso
&& !c_dialect_cxx ()
&& TARGET_FLT_EVAL_METHOD != 0
- && flag_excess_precision != EXCESS_PRECISION_STANDARD)
+ && flag_excess_precision_cmdline != EXCESS_PRECISION_STANDARD)
ret = 0;
/* Various options are contrary to IEEE 754 semantics. */
--
Joseph S. Myers
jos...@codesourcery.com
