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[Committed] Further signbit/copysign improvements (part 1/2)
- From: Roger Sayle <roger at eyesopen dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Richard Henderson <rth at redhat dot com>
- Date: Tue, 15 Mar 2005 14:01:24 -0700 (MST)
- Subject: [Committed] Further signbit/copysign improvements (part 1/2)
This patch implements some refinements to my recent signbitl patch
suggested by Richard Henderson. Firstly, we now specify signbit_ro
values for c4x's single and extended floating point formats (which
use a two's complement encoding rather than the more usual sign and
magnitude encoding). And secondly, we tweak expand_copysign to use
signbit_ro when using "expand_copysign_absneg" for RTL expansion,
and signbit_rw when using "expand_copysign_bit". The former only
requires the "read-only" signbit to determine the sign of operand 1,
but the latter attempts to invert the signbit requiring "signbit_rw".
Further changes/clean-ups to the rs6000 backend will be part 2/2.
The following patch has been tested on i686-pc-linux-gnu with a full
"make bootstrap", all default languages, and regression tested with a
top-level "make -k check" with no new failures.
Committed to mainline CVS.
2005-03-15 Roger Sayle <roger@eyesopen.com>
Richard Henderson <rth@redhat.com>
* real.c (c4x_single_format, c4x_extended_format): Provide values
for signbit_ro for c4x's single and extended floating point formats.
* optabs.c (expand_copysign): Use the floating point format's
signbit_ro for expanding via expand_copysign_absneg, and it's
signbit_rw field for expanding via expand_copysign_bit.
Index: real.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/real.c,v
retrieving revision 1.153
diff -c -3 -p -r1.153 real.c
*** real.c 15 Mar 2005 04:23:59 -0000 1.153
--- real.c 15 Mar 2005 16:38:45 -0000
*************** const struct real_format c4x_single_form
*** 4414,4420 ****
24,
-126,
128,
! -1,
-1,
false,
false,
--- 4414,4420 ----
24,
-126,
128,
! 23,
-1,
false,
false,
*************** const struct real_format c4x_extended_fo
*** 4433,4439 ****
32,
-126,
128,
! -1,
-1,
false,
false,
--- 4433,4439 ----
32,
-126,
128,
! 31,
-1,
false,
false,
Index: optabs.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/optabs.c,v
retrieving revision 1.262
diff -c -3 -p -r1.262 optabs.c
*** optabs.c 15 Mar 2005 04:24:02 -0000 1.262
--- optabs.c 15 Mar 2005 16:38:47 -0000
*************** expand_copysign (rtx op0, rtx op1, rtx t
*** 2865,2871 ****
{
enum machine_mode mode = GET_MODE (op0);
const struct real_format *fmt;
- int bitpos;
bool op0_is_abs;
rtx temp;
--- 2865,2870 ----
*************** expand_copysign (rtx op0, rtx op1, rtx t
*** 2882,2891 ****
if (fmt == NULL || !fmt->has_signed_zero)
return NULL_RTX;
- bitpos = fmt->signbit_rw;
- if (bitpos < 0)
- return NULL_RTX;
-
op0_is_abs = false;
if (GET_CODE (op0) == CONST_DOUBLE)
{
--- 2881,2886 ----
*************** expand_copysign (rtx op0, rtx op1, rtx t
*** 2894,2910 ****
op0_is_abs = true;
}
! if (GET_CODE (op0) == CONST_DOUBLE
! || (neg_optab->handlers[mode].insn_code != CODE_FOR_nothing
! && abs_optab->handlers[mode].insn_code != CODE_FOR_nothing))
{
temp = expand_copysign_absneg (mode, op0, op1, target,
! bitpos, op0_is_abs);
if (temp)
return temp;
}
! return expand_copysign_bit (mode, op0, op1, target, bitpos, op0_is_abs);
}
/* Generate an instruction whose insn-code is INSN_CODE,
--- 2889,2909 ----
op0_is_abs = true;
}
! if (fmt->signbit_ro >= 0
! && (GET_CODE (op0) == CONST_DOUBLE
! || (neg_optab->handlers[mode].insn_code != CODE_FOR_nothing
! && abs_optab->handlers[mode].insn_code != CODE_FOR_nothing)))
{
temp = expand_copysign_absneg (mode, op0, op1, target,
! fmt->signbit_ro, op0_is_abs);
if (temp)
return temp;
}
! if (fmt->signbit_rw < 0)
! return NULL_RTX;
! return expand_copysign_bit (mode, op0, op1, target,
! fmt->signbit_rw, op0_is_abs);
}
/* Generate an instruction whose insn-code is INSN_CODE,
Roger
--