---
This patch was approved in the original form, and the delta to here would
apply under the obvious rule:
https://gcc.gnu.org/ml/gcc-patches/2016-09/msg02414.html
---
On Fri, Sep 30, 2016 at 11:28:28AM -0600, Jeff Law wrote:
> On 09/30/2016 11:01 AM, James Greenhalgh wrote:
> >
> >Hi,
> >
> >This patch ports the logic from m68k's TARGET_FLT_EVAL_METHOD to the new
> >target hook TARGET_C_EXCESS_PRECISION.
> >
> >Patch tested by building an m68k-none-elf toolchain and running
> >m68k.exp (without the ability to execute) with no regressions, and manually
> >inspecting the output assembly code when compiling
> >testsuite/gcc.target/i386/excess-precision* to show no difference in
> >code-generation.
> >
> >OK?
> >
> >Thanks,
> >James
> >
> >---
> >gcc/
> >
> >2016-09-30 James Greenhalgh <james.greenha...@arm.com>
> >
> > * config/m68k/m68k.c (m68k_excess_precision): New.
> > (TARGET_C_EXCESS_PRECISION): Define.
> OK when prereqs are approved. Similarly for other targets where you
> needed to add this hook.
Thanks Jeff, Andreas,
I spotted a very silly bug when I was retesting this patch set - when I
swapped the namespace for the new traget macro it changed from
TARGET_EXCESS_PRECISION to TARGET_C_EXCESS_PRECISION but I failed to
update the m68k patch to reflect that.
This second revision fixes that (obvious) oversight.
Thanks,
James
---
gcc/
2016-11-09 James Greenhalgh <james.greenha...@arm.com>
* config/m68k/m68k.c (m68k_excess_precision): New.
(TARGET_C_EXCESS_PRECISION): Define.
diff --git a/gcc/config/m68k/m68k.c b/gcc/config/m68k/m68k.c
index ce56692..22165d6 100644
--- a/gcc/config/m68k/m68k.c
+++ b/gcc/config/m68k/m68k.c
@@ -183,6 +183,8 @@ static rtx m68k_function_arg (cumulative_args_t, machine_mode,
static bool m68k_cannot_force_const_mem (machine_mode mode, rtx x);
static bool m68k_output_addr_const_extra (FILE *, rtx);
static void m68k_init_sync_libfuncs (void) ATTRIBUTE_UNUSED;
+static enum flt_eval_method
+m68k_excess_precision (enum excess_precision_type);
/* Initialize the GCC target structure. */
@@ -323,6 +325,9 @@ static void m68k_init_sync_libfuncs (void) ATTRIBUTE_UNUSED;
#undef TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA
#define TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA m68k_output_addr_const_extra
+#undef TARGET_C_EXCESS_PRECISION
+#define TARGET_C_EXCESS_PRECISION m68k_excess_precision
+
/* The value stored by TAS. */
#undef TARGET_ATOMIC_TEST_AND_SET_TRUEVAL
#define TARGET_ATOMIC_TEST_AND_SET_TRUEVAL 128
@@ -6532,4 +6537,36 @@ m68k_epilogue_uses (int regno ATTRIBUTE_UNUSED)
== m68k_fk_interrupt_handler));
}
+
+/* Implement TARGET_C_EXCESS_PRECISION.
+
+ Set the value of FLT_EVAL_METHOD in float.h. When using 68040 fp
+ instructions, we get proper intermediate rounding, otherwise we
+ get extended precision results. */
+
+static enum flt_eval_method
+m68k_excess_precision (enum excess_precision_type type)
+{
+ switch (type)
+ {
+ 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:
+ case EXCESS_PRECISION_TYPE_IMPLICIT:
+ /* Otherwise, the excess precision we want when we are
+ in a standards compliant mode, and the implicit precision we
+ provide can be identical. */
+ if (TARGET_68040 || ! TARGET_68881)
+ return FLT_EVAL_METHOD_PROMOTE_TO_FLOAT;
+
+ return FLT_EVAL_METHOD_PROMOTE_TO_LONG_DOUBLE;
+ default:
+ gcc_unreachable ();
+ }
+ return FLT_EVAL_METHOD_UNPREDICTABLE;
+}
+
#include "gt-m68k.h"
