James Greenhalgh wrote:
> This is mostly OK, but I think you lose one case we previosuly permitted,
> buried in aarch64_classify_address (the CONST case).
>
> OK with that case handled too (assuming that passes a bootstrap and test).
That case is already handled. The CONST case handles the constant addresses,
and the remaining ones are LABEL_REFs, which is also handled. So I don't see
what case could be missing...
I've tweaked the code to use split_const like elsewhere:
2017-10-31 Wilco Dijkstra <wdijk...@arm.com>
* config/aarch64/aarch64.c (aarch64_legitimate_constant_p):
Return true for more constants, symbols and label references.
(aarch64_valid_floating_const): Remove unused function.
--
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index
6ab6092e1e518460e69d4c59ce5c1717f996f3db..1d7a5102d4f9f4dc9d4658df466231c47e3ca165
100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -10396,51 +10396,49 @@ aarch64_legitimate_pic_operand_p (rtx x)
return true;
}
-/* Return true if X holds either a quarter-precision or
- floating-point +0.0 constant. */
-static bool
-aarch64_valid_floating_const (rtx x)
-{
- if (!CONST_DOUBLE_P (x))
- return false;
-
- /* This call determines which constants can be used in mov<mode>
- as integer moves instead of constant loads. */
- if (aarch64_float_const_rtx_p (x))
- return true;
-
- return aarch64_float_const_representable_p (x);
-}
+/* Implement TARGET_LEGITIMATE_CONSTANT_P hook. Return true for constants
+ that should be rematerialized rather than spilled. */
static bool
aarch64_legitimate_constant_p (machine_mode mode, rtx x)
{
+ /* Support CSE and rematerialization of common constants. */
+ if (CONST_INT_P (x) || CONST_DOUBLE_P (x) || GET_CODE (x) == CONST_VECTOR)
+ return true;
+
/* Do not allow vector struct mode constants. We could support
0 and -1 easily, but they need support in aarch64-simd.md. */
- if (TARGET_SIMD && aarch64_vect_struct_mode_p (mode))
+ if (aarch64_vect_struct_mode_p (mode))
return false;
- /* For these cases we never want to use a literal load.
- As such we have to prevent the compiler from forcing these
- to memory. */
- if ((GET_CODE (x) == CONST_VECTOR
- && aarch64_simd_valid_immediate (x, mode, false, NULL))
- || CONST_INT_P (x)
- || aarch64_valid_floating_const (x)
- || aarch64_can_const_movi_rtx_p (x, mode)
- || aarch64_float_const_rtx_p (x))
- return !targetm.cannot_force_const_mem (mode, x);
+ /* Do not allow wide int constants - this requires support in movti. */
+ if (CONST_WIDE_INT_P (x))
+ return false;
- if (GET_CODE (x) == HIGH
- && aarch64_valid_symref (XEXP (x, 0), GET_MODE (XEXP (x, 0))))
- return true;
+ /* Do not allow const (plus (anchor_symbol, const_int)). */
+ if (GET_CODE (x) == CONST)
+ {
+ rtx offset;
+
+ split_const (x, &x, &offset);
+
+ if (SYMBOL_REF_P (x) && SYMBOL_REF_ANCHOR_P (x))
+ return false;
+ }
+
+ if (GET_CODE (x) == HIGH)
+ x = XEXP (x, 0);
/* Treat symbols as constants. Avoid TLS symbols as they are complex,
so spilling them is better than rematerialization. */
if (SYMBOL_REF_P (x) && !SYMBOL_REF_TLS_MODEL (x))
return true;
- return aarch64_constant_address_p (x);
+ /* Label references are always constant. */
+ if (GET_CODE (x) == LABEL_REF)
+ return true;
+
+ return false;
}
rtx
