simplify_truncation changes the truncation of many operations into
the operation on the truncation. This patch makes this code also
handle extracts.
Tested on powerpc64-linux. With this patch the rlwimi testcases work.
Is this okay for trunk?
Segher
---
gcc/simplify-rtx.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index fde2443..e8c142c 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -742,6 +742,36 @@ simplify_truncation (machine_mode mode, rtx op,
}
}
+ /* Turn (truncate:M1 (*_extract:M2 (reg:M2) (len) (pos))) into
+ (*_extract:M1 (truncate:M1 (reg:M2)) (len) (pos')) if possible without
+ changing len. */
+ if ((GET_CODE (op) == ZERO_EXTRACT || GET_CODE (op) == SIGN_EXTRACT)
+ && REG_P (XEXP (op, 0))
+ && CONST_INT_P (XEXP (op, 1))
+ && CONST_INT_P (XEXP (op, 2)))
+ {
+ rtx op0 = XEXP (op, 0);
+ unsigned HOST_WIDE_INT len = UINTVAL (XEXP (op, 1));
+ unsigned HOST_WIDE_INT pos = UINTVAL (XEXP (op, 2));
+ if (BITS_BIG_ENDIAN && pos >= op_precision - precision)
+ {
+ op0 = simplify_gen_unary (TRUNCATE, mode, op0, GET_MODE (op0));
+ if (op0)
+ {
+ pos -= op_precision - precision;
+ return simplify_gen_ternary (GET_CODE (op), mode, mode, op0,
+ XEXP (op, 1), GEN_INT (pos));
+ }
+ }
+ else if (!BITS_BIG_ENDIAN && precision >= len + pos)
+ {
+ op0 = simplify_gen_unary (TRUNCATE, mode, op0, GET_MODE (op0));
+ if (op0)
+ return simplify_gen_ternary (GET_CODE (op), mode, mode, op0,
+ XEXP (op, 1), XEXP (op, 2));
+ }
+ }
+
/* Recognize a word extraction from a multi-word subreg. */
if ((GET_CODE (op) == LSHIFTRT
|| GET_CODE (op) == ASHIFTRT)
--
1.9.3
