Re: [ARM] Add support for overflow add, sub, and neg operations
Hi Michael, Sorry for the delay in reviewing. A few comments at the bottom. On 29/03/16 00:19, Michael Collison wrote: An updated patch that resolves the issues with thumb2 support and adds test cases as requested. Looking to check this into GCC 7 stage1 when it opens. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): 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. On 02/29/2016 04:13 AM, Kyrill Tkachov wrote: On 26/02/16 10:32, Michael Collison wrote: On 02/25/2016 02:51 AM, Kyrill Tkachov wrote: Hi Michael, On 24/02/16 23:02, Michael Collison wrote: This patch adds support for builtin overflow of add, subtract and negate. This patch is targeted for gcc 7 stage 1. It was tested with no regressions in arm and thumb modes on the following targets: arm-non-linux-gnueabi arm-non-linux-gnuabihf armeb-none-linux-gnuabihf arm-non-eabi I'll have a deeper look once we're closer to GCC 7 development. I've got a few comments in the meantime. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): New patterns to support unsigned builtin subtract overflow operations. (negvsi3, negvdi3, negdi2_compre, negsi2_carryin_compare): New patterns to support builtin overflow negate operations. Can you please summarise what sequences are generated for these operations, and how they are better than the default fallback sequences. Sure 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 overflow patch this now generates: addsr0, r0, r1 movvs r3, #1 movvc r3, #0 str r3, [r2] bx lr Thanks! That looks much better. Also, we'd need tests for each of these overflow operations, since these are pretty complex patterns that are being added. The patterns are tested now most notably by tests in: c-c++-common/torture/builtin-arith-overflow*.c I had a few failures I resolved so the builtin overflow arithmetic functions are definitely being exercised. Great, that gives me more confidence on the correctness aspects but... Also, you may want to consider splitting this into a patch series, each adding a single overflow operation, together with its tests. That way it will be easier to keep track of which pattern applies to which use case and they can go in independently of each other. Let me know if you still fell the same way given the existing test cases. ... I'd like us to still have scan-assembler tests. The torture tests exercise the correctness, but we'd want tests to catch regressions where we stop generating the new patterns due to other optimisation changes, which would lead to code quality regressions. So I'd like us to have scan-assembler tests for these sequences to make sure we generate the right instructions. Thanks,
Re: [ARM] Add support for overflow add, sub, and neg operations
Hi Michael, On 24/02/16 23:02, Michael Collison wrote: This patch adds support for builtin overflow of add, subtract and negate. This patch is targeted for gcc 7 stage 1. It was tested with no regressions in arm and thumb modes on the following targets: arm-non-linux-gnueabi arm-non-linux-gnuabihf armeb-none-linux-gnuabihf arm-non-eabi I'll have a deeper look once we're closer to GCC 7 development. I've got a few comments in the meantime. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): New patterns to support unsigned builtin subtract overflow operations. (negvsi3, negvdi3, negdi2_compre, negsi2_carryin_compare): New patterns to support builtin overflow negate operations. Can you please summarise what sequences are generated for these operations, and how they are better than the default fallback sequences. Also, we'd need tests for each of these overflow operations, since these are pretty complex patterns that are being added. Also, you may want to consider splitting this into a patch series, each adding a single overflow operation, together with its tests. That way it will be easier to keep track of which pattern applies to which use case and they can go in independently of each other. +(define_expand "uaddv4" + [(match_operand:SIDI 0 "register_operand") + (match_operand:SIDI 1 "register_operand") + (match_operand:SIDI 2 "register_operand") + (match_operand 3 "")] + "TARGET_ARM" +{ + emit_insn (gen_add3_compareC (operands[0], operands[1], operands[2])); + + rtx x; + x = gen_rtx_NE (VOIDmode, gen_rtx_REG (CC_Cmode, CC_REGNUM), const0_rtx); + x = gen_rtx_IF_THEN_ELSE (VOIDmode, x, + gen_rtx_LABEL_REF (VOIDmode, operands[3]), + pc_rtx); + emit_jump_insn (gen_rtx_SET (pc_rtx, x)); + DONE; +}) + I notice this and many other patterns in this patch are guarded on TARGET_ARM. Is there any reason why they should be restricted to arm state and not be TARGET_32BIT ? Thanks, Kyrill
Re: [ARM] Add support for overflow add, sub, and neg operations
On 02/25/2016 02:51 AM, Kyrill Tkachov wrote: Hi Michael, On 24/02/16 23:02, Michael Collison wrote: This patch adds support for builtin overflow of add, subtract and negate. This patch is targeted for gcc 7 stage 1. It was tested with no regressions in arm and thumb modes on the following targets: arm-non-linux-gnueabi arm-non-linux-gnuabihf armeb-none-linux-gnuabihf arm-non-eabi I'll have a deeper look once we're closer to GCC 7 development. I've got a few comments in the meantime. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): New patterns to support unsigned builtin subtract overflow operations. (negvsi3, negvdi3, negdi2_compre, negsi2_carryin_compare): New patterns to support builtin overflow negate operations. Can you please summarise what sequences are generated for these operations, and how they are better than the default fallback sequences. Sure 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 overflow patch this now generates: addsr0, r0, r1 movvs r3, #1 movvc r3, #0 str r3, [r2] bx lr Also, we'd need tests for each of these overflow operations, since these are pretty complex patterns that are being added. The patterns are tested now most notably by tests in: c-c++-common/torture/builtin-arith-overflow*.c I had a few failures I resolved so the builtin overflow arithmetic functions are definitely being exercised. Also, you may want to consider splitting this into a patch series, each adding a single overflow operation, together with its tests. That way it will be easier to keep track of which pattern applies to which use case and they can go in independently of each other. Let me know if you still fell the same way given the existing test cases. +(define_expand "uaddv4" + [(match_operand:SIDI 0 "register_operand") + (match_operand:SIDI 1 "register_operand") + (match_operand:SIDI 2 "register_operand") + (match_operand 3 "")] + "TARGET_ARM" +{ + emit_insn (gen_add3_compareC (operands[0], operands[1], operands[2])); + + rtx x; + x = gen_rtx_NE (VOIDmode, gen_rtx_REG (CC_Cmode, CC_REGNUM), const0_rtx); + x = gen_rtx_IF_THEN_ELSE (VOIDmode, x, +gen_rtx_LABEL_REF (VOIDmode, operands[3]), +pc_rtx); + emit_jump_insn (gen_rtx_SET (pc_rtx, x)); + DONE; +}) + I notice this and many other patterns in this patch are guarded on TARGET_ARM. Is there any reason why they should be restricted to arm state and not be TARGET_32BIT ? I thought about this as well. I will test will TARGET_32BIT and get back to you. Thanks, Kyrill -- Michael Collison Linaro Toolchain Working Group michael.colli...@linaro.org
Re: [ARM] Add support for overflow add, sub, and neg operations
On 26/02/16 10:32, Michael Collison wrote: On 02/25/2016 02:51 AM, Kyrill Tkachov wrote: Hi Michael, On 24/02/16 23:02, Michael Collison wrote: This patch adds support for builtin overflow of add, subtract and negate. This patch is targeted for gcc 7 stage 1. It was tested with no regressions in arm and thumb modes on the following targets: arm-non-linux-gnueabi arm-non-linux-gnuabihf armeb-none-linux-gnuabihf arm-non-eabi I'll have a deeper look once we're closer to GCC 7 development. I've got a few comments in the meantime. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): New patterns to support unsigned builtin subtract overflow operations. (negvsi3, negvdi3, negdi2_compre, negsi2_carryin_compare): New patterns to support builtin overflow negate operations. Can you please summarise what sequences are generated for these operations, and how they are better than the default fallback sequences. Sure 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 overflow patch this now generates: addsr0, r0, r1 movvs r3, #1 movvc r3, #0 str r3, [r2] bx lr Thanks! That looks much better. Also, we'd need tests for each of these overflow operations, since these are pretty complex patterns that are being added. The patterns are tested now most notably by tests in: c-c++-common/torture/builtin-arith-overflow*.c I had a few failures I resolved so the builtin overflow arithmetic functions are definitely being exercised. Great, that gives me more confidence on the correctness aspects but... Also, you may want to consider splitting this into a patch series, each adding a single overflow operation, together with its tests. That way it will be easier to keep track of which pattern applies to which use case and they can go in independently of each other. Let me know if you still fell the same way given the existing test cases. ... I'd like us to still have scan-assembler tests. The torture tests exercise the correctness, but we'd want tests to catch regressions where we stop generating the new patterns due to other optimisation changes, which would lead to code quality regressions. So I'd like us to have scan-assembler tests for these sequences to make sure we generate the right instructions. Thanks, Kyrill +(define_expand "uaddv4" + [(match_operand:SIDI 0 "register_operand") + (match_operand:SIDI 1 "register_operand") + (match_operand:SIDI 2 "register_operand") + (match_operand 3 "")] + "TARGET_ARM" +{ + emit_insn (gen_add3_compareC (operands[0], operands[1], operands[2])); + + rtx x; + x = gen_rtx_NE (VOIDmode, gen_rtx_REG (CC_Cmode, CC_REGNUM), const0_rtx); + x = gen_rtx_IF_THEN_ELSE (VOIDmode, x, +gen_rtx_LABEL_REF (VOIDmode, operands[3]), +pc_rtx); + emit_jump_insn (gen_rtx_SET (pc_rtx, x)); + DONE; +}) + I notice this and many other patterns in this patch are guarded on TARGET_ARM. Is there any reason why they should be restricted to arm state and not be TARGET_32BIT ? I thought about this as well. I will test will TARGET_32BIT and get back to you. Thanks, Kyrill
Re: [ARM] Add support for overflow add, sub, and neg operations
On 2/29/2016 4:13 AM, Kyrill Tkachov wrote: On 26/02/16 10:32, Michael Collison wrote: On 02/25/2016 02:51 AM, Kyrill Tkachov wrote: Hi Michael, On 24/02/16 23:02, Michael Collison wrote: This patch adds support for builtin overflow of add, subtract and negate. This patch is targeted for gcc 7 stage 1. It was tested with no regressions in arm and thumb modes on the following targets: arm-non-linux-gnueabi arm-non-linux-gnuabihf armeb-none-linux-gnuabihf arm-non-eabi I'll have a deeper look once we're closer to GCC 7 development. I've got a few comments in the meantime. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): New patterns to support unsigned builtin subtract overflow operations. (negvsi3, negvdi3, negdi2_compre, negsi2_carryin_compare): New patterns to support builtin overflow negate operations. Can you please summarise what sequences are generated for these operations, and how they are better than the default fallback sequences. Sure 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 overflow patch this now generates: addsr0, r0, r1 movvs r3, #1 movvc r3, #0 str r3, [r2] bx lr Thanks! That looks much better. Also, we'd need tests for each of these overflow operations, since these are pretty complex patterns that are being added. The patterns are tested now most notably by tests in: c-c++-common/torture/builtin-arith-overflow*.c I had a few failures I resolved so the builtin overflow arithmetic functions are definitely being exercised. Great, that gives me more confidence on the correctness aspects but... Not so fast. I went back and changed the TARGET_ARM conditions to TARGET_32BIT. When I did this some of the test cases fail in thumb2 mode. I was a little surprised by this result since I generate the same rtl in both modes in almost all cases. I am investigating. Also, you may want to consider splitting this into a patch series, each adding a single overflow operation, together with its tests. That way it will be easier to keep track of which pattern applies to which use case and they can go in independently of each other. Let me know if you still fell the same way given the existing test cases. ... I'd like us to still have scan-assembler tests. The torture tests exercise the correctness, but we'd want tests to catch regressions where we stop generating the new patterns due to other optimisation changes, which would lead to code quality regressions. So I'd like us to have scan-assembler tests for these sequences to make sure we generate the right instructions. I will definitely write some scan-assembler tests. Thanks for the feedback. Thanks, Kyrill +(define_expand "uaddv4" + [(match_operand:SIDI 0 "register_operand") + (match_operand:SIDI 1 "register_operand") + (match_operand:SIDI 2 "register_operand") + (match_operand 3 "")] + "TARGET_ARM" +{ + emit_insn (gen_add3_compareC (operands[0], operands[1], operands[2])); + + rtx x; + x = gen_rtx_NE (VOIDmode, gen_rtx_REG (CC_Cmode, CC_REGNUM), const0_rtx); + x = gen_rtx_IF_THEN_ELSE (VOIDmode, x, +gen_rtx_LABEL_REF (VOIDmode, operands[3]), +pc_rtx); + emit_jump_insn (gen_rtx_SET (pc_rtx, x)); + DONE; +}) + I notice this and many other patterns in this patch are guarded on TARGET_ARM. Is there any reason why they should be restricted to arm state and not be TARGET_32BIT ? I thought about this as well. I will test will TARGET_32BIT and get back to you. Thanks, Kyrill
Re: [ARM] Add support for overflow add, sub, and neg operations
An updated patch that resolves the issues with thumb2 support and adds test cases as requested. Looking to check this into GCC 7 stage1 when it opens. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): 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. On 02/29/2016 04:13 AM, Kyrill Tkachov wrote: On 26/02/16 10:32, Michael Collison wrote: On 02/25/2016 02:51 AM, Kyrill Tkachov wrote: Hi Michael, On 24/02/16 23:02, Michael Collison wrote: This patch adds support for builtin overflow of add, subtract and negate. This patch is targeted for gcc 7 stage 1. It was tested with no regressions in arm and thumb modes on the following targets: arm-non-linux-gnueabi arm-non-linux-gnuabihf armeb-none-linux-gnuabihf arm-non-eabi I'll have a deeper look once we're closer to GCC 7 development. I've got a few comments in the meantime. 2016-02-24 Michael Collison * 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. * config/arm/arm.md (addv4, add3_compareV, addsi3_compareV_upper): New patterns to support signed builtin overflow add operations. (uaddv4, add3_compareC, addsi3_compareV_upper): New patterns to support unsigned builtin add overflow operations. (subv4, sub3_compare1): New patterns to support signed builtin overflow subtract operations, (usubv4): New patterns to support unsigned builtin subtract overflow operations. (negvsi3, negvdi3, negdi2_compre, negsi2_carryin_compare): New patterns to support builtin overflow negate operations. Can you please summarise what sequences are generated for these operations, and how they are better than the default fallback sequences. Sure 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 overflow patch this now generates: addsr0, r0, r1 movvs r3, #1 movvc r3, #0 str r3, [r2] bx lr Thanks! That looks much better. Also, we'd need tests for each of these overflow operations, since these are pretty complex patterns that are being added. The patterns are tested now most notably by tests in: c-c++-common/torture/builtin-arith-overflow*.c I had a few failures I resolved so the builtin overflow arithmetic functions are definitely being exercised. Great, that gives me more confidence on the correctness aspects but... Also, you may want to consider splitting this into a patch series, each adding a single overflow operation, together with its tests. That way it will be easier to keep track of which pattern applies to which use case and they can go in independently of each other. Let me know if you still fell the same way given the existing test cases. ... I'd like us to still have scan-assembler tests. The torture tests exercise the correctness, but we'd want tests to catch regressions where we stop generating the new patterns due to other optimisation changes, which would lead to code quality regressions. So I'd like us to have scan-assembler tests for these sequences to make sure we generate the right instructions. Thanks, Kyrill +(define_expand "uaddv4" + [(match_operand:SIDI 0 "register_operand") + (match_operand:SIDI 1 "regi
[Ping] Re: [ARM] Add support for overflow add, sub, and neg operations
Ping. Previous Patch posted here: https://gcc.gnu.org/ml/gcc-patches/2016-03/msg01472.html -- Michael Collison Linaro Toolchain Working Group michael.colli...@linaro.org
[Ping ^ 2] Re: [ARM] Add support for overflow add, sub, and neg operations
Ping. Previous Patch posted here: https://gcc.gnu.org/ml/gcc-patches/2016-03/msg01472.html
[Ping ^ 2] Re: [ARM] Add support for overflow add, sub, and neg operations
Ping. Previous Patch posted here: https://gcc.gnu.org/ml/gcc-patches/2016-03/msg01472.html