On 2 August 2016 at 10:13, Michael Collison <michael.colli...@arm.com> 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?
>
Hi Michael,
I've run validations with your patch, and I am seeing several failures
during tests execution:
http://people.linaro.org/~christophe.lyon/cross-validation/gcc-test-patches/239008-bugzilla-69663-upstream-final/report-build-info.html
I'm using qemu 2.6.0.
Did you run validation on actual HW? It could be a qemu bug, but I
haven't tried to manually reproduce the problem yet.
Christophe.
> 2016-07-27 Michael Collison <michael.colli...@linaro.org>
> Michael Collison <michael.colli...@arm.com>
>
> * 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.
