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[Patch 3/17] Implement TARGET_C_EXCESS_PRECISION for s390

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* config/s390/s390.c (s390_excess_precision): New.
	(TARGET_C_EXCESS_PRECISION): Define.

From-SVN: r242773
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James Greenhalgh 2016-11-23 17:16:29 +00:00 committed by James Greenhalgh
parent e97dfd54b7
commit 638108bd67
2 changed files with 45 additions and 0 deletions
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gcc/ChangeLog
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@ -1,3 +1,8 @@
2016-11-23 James Greenhalgh <james.greenhalgh@arm.com>
* config/s390/s390.c (s390_excess_precision): New.
(TARGET_C_EXCESS_PRECISION): Define.
2016-11-23 James Greenhalgh <james.greenhalgh@arm.com>
* config/i386/i386.c (ix86_excess_precision): New.

40
gcc/config/s390/s390.c
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@ -15260,6 +15260,43 @@ s390_invalid_binary_op (int op ATTRIBUTE_UNUSED, const_tree type1, const_tree ty
return NULL;
}
/* Implement TARGET_C_EXCESS_PRECISION.
FIXME: For historical reasons, float_t and double_t are typedef'ed to
double on s390, causing operations on float_t to operate in a higher
precision than is necessary. However, it is not the case that SFmode
operations have implicit excess precision, and we generate more optimal
code if we let the compiler know no implicit extra precision is added.
That means when we are compiling with -fexcess-precision=fast, the value
we set for FLT_EVAL_METHOD will be out of line with the actual precision of
float_t (though they would be correct for -fexcess-precision=standard).
A complete fix would modify glibc to remove the unnecessary typedef
of float_t to double. */
static enum flt_eval_method
s390_excess_precision (enum excess_precision_type type)
{
switch (type)
{
case EXCESS_PRECISION_TYPE_IMPLICIT:
case EXCESS_PRECISION_TYPE_FAST:
/* The fastest type to promote to will always be the native type,
whether that occurs with implicit excess precision or
otherwise. */
return FLT_EVAL_METHOD_PROMOTE_TO_FLOAT;
case EXCESS_PRECISION_TYPE_STANDARD:
/* Otherwise, when we are in a standards compliant mode, to
ensure consistency with the implementation in glibc, report that
float is evaluated to the range and precision of double. */
return FLT_EVAL_METHOD_PROMOTE_TO_DOUBLE;
default:
gcc_unreachable ();
}
return FLT_EVAL_METHOD_UNPREDICTABLE;
}
/* Initialize GCC target structure. */
#undef TARGET_ASM_ALIGNED_HI_OP
@ -15320,6 +15357,9 @@ s390_invalid_binary_op (int op ATTRIBUTE_UNUSED, const_tree type1, const_tree ty
#undef TARGET_ASM_CAN_OUTPUT_MI_THUNK
#define TARGET_ASM_CAN_OUTPUT_MI_THUNK hook_bool_const_tree_hwi_hwi_const_tree_true
#undef TARGET_C_EXCESS_PRECISION
#define TARGET_C_EXCESS_PRECISION s390_excess_precision
#undef TARGET_SCHED_ADJUST_PRIORITY
#define TARGET_SCHED_ADJUST_PRIORITY s390_adjust_priority
#undef TARGET_SCHED_ISSUE_RATE