Hi Michael,
On 02/08/16 09:13, Michael Collison wrote:
Hi,
This patch improves code generations for builtin arithmetic overflow operations
for the arm backend. As an example for a simple test case such as:
int
fn3 (int x, int y, int *ovf)
{
int res;
*ovf = __builtin_sadd_overflow (x, y, &res);
return res;
}
Current trunk at -O2 generates
fn3:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
cmp r1, #0
mov r3, #0
add r1, r0, r1
blt .L4
cmp r1, r0
blt .L3
.L2:
str r3, [r2]
mov r0, r1
bx lr
.L4:
cmp r1, r0
ble .L2
.L3:
mov r3, #1
b .L2
With the patch this now generates:
adds r0, r0, r1
movvs r3, #1
movvc r3, #0
str r3, [r2]
bx lr
Ok for trunk?
Ok assuming bootstrap and test on arm-none-linux-gnueabihf is clean.
with a couple of ChangeLog nits below.
Thanks for working through the iterations.
Thanks,
Kyrill
2016-07-27 Michael Collison <michael.colli...@linaro.org>
Michael Collison <michael.colli...@arm.com>
Two spaces between name and email address.
* config/arm/arm-modes.def: Add new condition code mode CC_V
to represent the overflow bit.
* config/arm/arm.c (maybe_get_arm_condition_code):
Add support for CC_Vmode.
(arm_gen_unlikely_cbranch): New function to generate common
rtl conditional branches for overflow patterns.
* config/arm/arm-protos.h: Add prototype for
arm_gen_unlikely_cbranch.
* config/arm/arm.md (addv<mode>4, add<mode>3_compareV,
addsi3_compareV_upper): New patterns to support signed
builtin overflow add operations.
(uaddv<mode>4, add<mode>3_compareC, addsi3_compareV_upper):
New patterns to support unsigned builtin add overflow operations.
(subv<mode>4, sub<mode>3_compare1): New patterns to support signed
builtin overflow subtract operations,
(usubv<mode>4): New patterns to support unsigned builtin subtract
overflow operations.
(negvsi3, negvdi3, negdi2_compare, negsi2_carryin_compare): New patterns
to support builtin overflow negate operations.
* gcc.target/arm/builtin_saddl.c: New testcase.
* gcc.target/arm/builtin_saddll.c: New testcase.
* gcc.target/arm/builtin_uaddl.c: New testcase.
* gcc.target/arm/builtin_uaddll.c: New testcase.
* gcc.target/arm/builtin_ssubl.c: New testcase.
* gcc.target/arm/builtin_ssubll.c: New testcase.
* gcc.target/arm/builtin_usubl.c: New testcase.
* gcc.target/arm/builtin_usubll.c: New testcase.
Please make sure the testsuite entries go into the ChangeLog file in
gcc/testsuite/
