Hello,
The following patch improves both the speed and code size for 64 bit signed
max for RL78:
it emits a library function call instead of emitting code for the 64 bit
max for every single time.
The signed max function which was added in libgcc is hand written, so more
optimal than what GCC generates.
The change can easily be seen on the following test case:
long long my_smaxdi3(long long x, long long y){
return (x > y)? x : y;
}
I did not add this to the regression as it very simple and there are test
cases in the regression which test this, for example
gcc.c-torture/execute/20000224-1.c and gcc.c-torture/execute/20021010-2.c
Regression test is OK, tested with the following command:
make -k check-gcc RUNTESTFLAGS=--target_board=rl78-sim
Please let me know if this is OK, Thank you!
Sebastian
Index: gcc/ChangeLog
===================================================================
--- gcc/ChangeLog (revision 255467)
+++ gcc/ChangeLog (working copy)
@@ -1,3 +1,7 @@
+2017-12-07 Sebastian Perta <sebastian.pe...@renesas.com>
+
+ * config/rl78/rl78.md: New define_expand "smaxdi3".
+
2017-12-07 Michael Matz <m...@suse.de>
Add unroll and jam pass
Index: gcc/config/rl78/rl78.md
===================================================================
--- gcc/config/rl78/rl78.md (revision 255467)
+++ gcc/config/rl78/rl78.md (working copy)
@@ -718,3 +718,13 @@
[(set_attr "valloc" "macax")
(set_attr "is_g13_muldiv_insn" "yes")]
)
+
+(define_expand "smaxdi3"
+ [(set (match_operand:DI 0 "nonimmediate_operand" "")
+ (smax:DI (match_operand:DI 1 "general_operand" "")
+ (match_operand:DI 2 "general_operand" "")))
+ ]
+ "optimize_size"
+ "rl78_emit_libcall (\"__smaxdi3\", SMAX, DImode, DImode, 3, operands);
+ DONE;"
+)
Index: libgcc/ChangeLog
===================================================================
--- libgcc/ChangeLog (revision 255467)
+++ libgcc/ChangeLog (working copy)
@@ -1,3 +1,9 @@
+2017-12-07 Sebastian Perta <sebastian.pe...@renesas.com>
+
+ * config/rl78/smaxdi3.S: New assembly file.
+ * config/rl78/t-rl78: Added smaxdi3.S to LIB2ADD.
+
+
2017-11-30 Michael Meissner <meiss...@linux.vnet.ibm.com>
* config/rs6000/_mulkc3.c (__mulkc3): Add forward declaration.
Index: libgcc/config/rl78/t-rl78
===================================================================
--- libgcc/config/rl78/t-rl78 (revision 255467)
+++ libgcc/config/rl78/t-rl78 (working copy)
@@ -32,7 +32,8 @@
$(srcdir)/config/rl78/fpmath-sf.S \
$(srcdir)/config/rl78/cmpsi2.S \
$(srcdir)/config/rl78/adddi3.S \
- $(srcdir)/config/rl78/subdi3.S
+ $(srcdir)/config/rl78/subdi3.S \
+ $(srcdir)/config/rl78/smaxdi3.S
LIB2FUNCS_EXCLUDE = _clzhi2 _clzsi2 _ctzhi2 _ctzsi2 \
_popcounthi2 _popcountsi2 \
Index: libgcc/config/rl78/smaxdi3.S
===================================================================
--- libgcc/config/rl78/smaxdi3.S (nonexistent)
+++ libgcc/config/rl78/smaxdi3.S (working copy)
@@ -0,0 +1,76 @@
+; Copyright (C) 2017 Free Software Foundation, Inc.
+; Contributed by Sebastian Perta.
+;
+; This file is free software; you can redistribute it and/or modify it
+; under the terms of the GNU General Public License as published by the
+; Free Software Foundation; either version 3, or (at your option) any
+; later version.
+;
+; This file is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+; General Public License for more details.
+;
+; Under Section 7 of GPL version 3, you are granted additional
+; permissions described in the GCC Runtime Library Exception, version
+; 3.1, as published by the Free Software Foundation.
+;
+; You should have received a copy of the GNU General Public License and
+; a copy of the GCC Runtime Library Exception along with this program;
+; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+; <http://www.gnu.org/licenses/>.
+
+
+#include "vregs.h"
+
+ .text
+
+START_FUNC ___smaxdi3
+
+ ; copy first argument/operand to the output registers
+ movw ax, [sp+4]
+ movw r8, ax
+ movw ax, [sp+6]
+ movw r10, ax
+ movw ax, [sp+8]
+ movw r12, ax
+ movw ax, [sp+10]
+ movw r14, ax
+
+ ; use 16-bit compares from the most significant words downto the least
significant ones
+ movw ax, [sp+18]
+ cmpw ax, r14
+ xor1 CY, a.7 ; first compare accounts for the
+ xor1 CY, r15.7 ; sign bits of the two operands
+ bh $.L1
+ bnz $.L2
+
+ movw ax, [sp+16]
+ cmpw ax, r12
+ bh $.L1
+ bnz $.L2
+
+ movw ax, [sp+14]
+ cmpw ax, r10
+ bh $.L1
+ bnz $.L2
+
+ movw ax, [sp+12]
+ cmpw ax, r8
+ bh $.L1
+ ret
+
+.L1:
+ ; copy second argument/operand to the output registers
+ movw ax, [sp+12]
+ movw r8, ax
+ movw ax, [sp+14]
+ movw r10, ax
+ movw ax, [sp+16]
+ movw r12, ax
+ movw ax, [sp+18]
+ movw r14, ax
+.L2:
+ ret
+
+END_FUNC ___smaxdi3
+
