More details of VSETVL bug: Loop: 10ddc: 9ed030d7 vmv1r.v v1,v13 10de0: b21040d7 vncvt.x.x.w v1,v1 10de4: 5e0785d7 vmv.v.v v11,v15 10de8: b700a5d7 vmacc.vv v11,v1,v16 10dec: a6e8a0d7 vmadd.vv v1,v17,v14 10df0: 26b7b5d7 vand.vi v11,v11,15 10df4: 0c75f7d7 vsetvli a5,a1,e8,mf2,ta,ma 10df8: 0c707557 vsetvli a0,zero,e8,mf2,ta,ma 10dfc: 2617b0d7 vand.vi v1,v1,15 10e00: 0c75f057 vsetvli zero,a1,e8,mf2,ta,ma 10e04: 8d9d sub a1,a1,a5 10e06: 020705a7 vse8.v v11,(a4) 10e0a: 0c77f057 vsetvli zero,a5,e8,mf2,ta,ma 10e0e: 020685a7 vse8.v v11,(a3) 10e12: 020600a7 vse8.v v1,(a2) 10e16: 973e add a4,a4,a5 10e18: 0c807557 vsetvli a0,zero,e16,m1,ta,ma 10e1c: 96be add a3,a3,a5 10e1e: 963e add a2,a2,a5 10e20: 02d606d7 vadd.vv v13,v13,v12 10e24: fdc5 bnez a1,10ddc <main+0xca0>
The vncvt.x.x.w consume e16m1 VTYPE vsetvl but it shouldn't, it should be e8mf2. This issue is fixed by recent refactor patch. juzhe.zh...@rivai.ai From: Juzhe-Zhong Date: 2023-10-18 18:25 To: gcc-patches CC: kito.cheng; kito.cheng; jeffreyalaw; rdapp.gcc; Juzhe-Zhong Subject: [PATCH V2] RISC-V: Fix failed hoist in LICM of vmv.v.x instruction Confirm dynamic LMUL algorithm works well for choosing LMUL = 4 for the PR: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111848 But it generate horrible register spillings. The root cause is that we didn't hoist the vmv.v.x outside the loop which increase the SLP loop register pressure. So, change the COSNT_VECTOR move into vec_duplicate splitter that we can gain better optimizations: 1. better LICM. 2. More opportunities of transforming 'vv' into 'vx' in the future. Before this patch: f3: ble a4,zero,.L8 csrr t0,vlenb slli t1,t0,4 csrr a6,vlenb sub sp,sp,t1 csrr a5,vlenb slli a6,a6,3 slli a5,a5,2 add a6,a6,sp vsetvli a7,zero,e16,m8,ta,ma slli a4,a4,3 vid.v v8 addi t6,a5,-1 vand.vi v8,v8,-2 neg t5,a5 vs8r.v v8,0(sp) vadd.vi v8,v8,1 vs8r.v v8,0(a6) j .L4 .L12: vsetvli a7,zero,e16,m8,ta,ma .L4: csrr t0,vlenb slli t0,t0,3 vl8re16.v v16,0(sp) add t0,t0,sp vmv.v.x v8,t6 mv t1,a4 vand.vv v24,v16,v8 mv a6,a4 vl8re16.v v16,0(t0) vand.vv v8,v16,v8 bleu a4,a5,.L3 mv a6,a5 .L3: vsetvli zero,a6,e8,m4,ta,ma vle8.v v20,0(a2) vle8.v v16,0(a3) vsetvli a7,zero,e8,m4,ta,ma vrgatherei16.vv v4,v20,v24 vadd.vv v4,v16,v4 vsetvli zero,a6,e8,m4,ta,ma vse8.v v4,0(a0) vle8.v v20,0(a2) vsetvli a7,zero,e8,m4,ta,ma vrgatherei16.vv v4,v20,v8 vadd.vv v4,v4,v16 vsetvli zero,a6,e8,m4,ta,ma vse8.v v4,0(a1) add a4,a4,t5 add a0,a0,a5 add a3,a3,a5 add a1,a1,a5 add a2,a2,a5 bgtu t1,a5,.L12 csrr t0,vlenb slli t1,t0,4 add sp,sp,t1 jr ra .L8: ret After this patch: f3: ble a4,zero,.L6 csrr a6,vlenb csrr a5,vlenb slli a6,a6,2 slli a5,a5,2 addi a6,a6,-1 slli a4,a4,3 neg t5,a5 vsetvli t1,zero,e16,m8,ta,ma vmv.v.x v24,a6 vid.v v8 vand.vi v8,v8,-2 vadd.vi v16,v8,1 vand.vv v8,v8,v24 vand.vv v16,v16,v24 .L4: mv t1,a4 mv a6,a4 bleu a4,a5,.L3 mv a6,a5 .L3: vsetvli zero,a6,e8,m4,ta,ma vle8.v v28,0(a2) vle8.v v24,0(a3) vsetvli a7,zero,e8,m4,ta,ma vrgatherei16.vv v4,v28,v8 vadd.vv v4,v24,v4 vsetvli zero,a6,e8,m4,ta,ma vse8.v v4,0(a0) vle8.v v28,0(a2) vsetvli a7,zero,e8,m4,ta,ma vrgatherei16.vv v4,v28,v16 vadd.vv v4,v4,v24 vsetvli zero,a6,e8,m4,ta,ma vse8.v v4,0(a1) add a4,a4,t5 add a0,a0,a5 add a3,a3,a5 add a1,a1,a5 add a2,a2,a5 bgtu t1,a5,.L4 .L6: ret Note that this patch triggers multiple FAILs: FAIL: gcc.target/riscv/rvv/autovec/cond/cond_arith_run-3.c execution test FAIL: gcc.target/riscv/rvv/autovec/cond/cond_arith_run-3.c execution test FAIL: gcc.target/riscv/rvv/autovec/cond/cond_arith_run-4.c execution test FAIL: gcc.target/riscv/rvv/autovec/cond/cond_arith_run-4.c execution test FAIL: gcc.target/riscv/rvv/autovec/cond/cond_arith_run-8.c execution test FAIL: gcc.target/riscv/rvv/autovec/cond/cond_arith_run-8.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_load_run-1.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_load_run-1.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_load_run-2.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_load_run-2.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_store_run-1.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_store_run-1.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_store_run-2.c execution test FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/strided_store_run-2.c execution test They failed are all because of bugs on VSETVL PASS: 10dd4: 0c707057 vsetvli zero,zero,e8,mf2,ta,ma 10dd8: 5e06b8d7 vmv.v.i v17,13 10ddc: 9ed030d7 vmv1r.v v1,v13 10de0: b21040d7 vncvt.x.x.w v1,v1 ----> raise illegal instruction since we don't have SEW = 8 -> SEW = 4 narrowing. 10de4: 5e0785d7 vmv.v.v v11,v15 Confirm the recent VSETVL refactor patch: https://gcc.gnu.org/pipermail/gcc-patches/2023-October/633231.html fixed all of them. So this patch should be committed after the VSETVL refactor patch. PR target/111848 gcc/ChangeLog: * config/riscv/riscv-selftests.cc (run_const_vector_selftests): Adapt selftest. * config/riscv/riscv-v.cc (expand_const_vector): Change it into vec_duplicate splitter. gcc/testsuite/ChangeLog: * gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-7.c: Adapt test. * gcc.dg/vect/costmodel/riscv/rvv/pr111848.c: New test. --- gcc/config/riscv/riscv-selftests.cc | 14 ++++---- gcc/config/riscv/riscv-v.cc | 27 ++++++++++++-- .../costmodel/riscv/rvv/dynamic-lmul2-7.c | 3 +- .../vect/costmodel/riscv/rvv/pr111848.c | 35 +++++++++++++++++++ 4 files changed, 68 insertions(+), 11 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/pr111848.c diff --git a/gcc/config/riscv/riscv-selftests.cc b/gcc/config/riscv/riscv-selftests.cc index cdc863ee4f7..0ac17fb70a1 100644 --- a/gcc/config/riscv/riscv-selftests.cc +++ b/gcc/config/riscv/riscv-selftests.cc @@ -267,15 +267,14 @@ run_const_vector_selftests (void) rtx dup = gen_const_vec_duplicate (mode, GEN_INT (val)); emit_move_insn (dest, dup); rtx_insn *insn = get_last_insn (); - rtx src = XEXP (SET_SRC (PATTERN (insn)), 1); + rtx src = SET_SRC (PATTERN (insn)); /* 1. Should be vmv.v.i for in rang of -16 ~ 15. 2. Should be vmv.v.x for exceed -16 ~ 15. */ if (IN_RANGE (val, -16, 15)) - ASSERT_TRUE (rtx_equal_p (src, dup)); - else ASSERT_TRUE ( - rtx_equal_p (src, - gen_rtx_VEC_DUPLICATE (mode, XEXP (src, 0)))); + rtx_equal_p (XEXP (SET_SRC (PATTERN (insn)), 1), dup)); + else + ASSERT_TRUE (GET_CODE (src) == VEC_DUPLICATE); end_sequence (); } } @@ -294,10 +293,9 @@ run_const_vector_selftests (void) rtx dup = gen_const_vec_duplicate (mode, ele); emit_move_insn (dest, dup); rtx_insn *insn = get_last_insn (); - rtx src = XEXP (SET_SRC (PATTERN (insn)), 1); + rtx src = SET_SRC (PATTERN (insn)); /* Should always be vfmv.v.f. */ - ASSERT_TRUE ( - rtx_equal_p (src, gen_rtx_VEC_DUPLICATE (mode, XEXP (src, 0)))); + ASSERT_TRUE (GET_CODE (src) == VEC_DUPLICATE); end_sequence (); } } diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc index 895c11d13fc..6116f5df504 100644 --- a/gcc/config/riscv/riscv-v.cc +++ b/gcc/config/riscv/riscv-v.cc @@ -1001,8 +1001,31 @@ expand_const_vector (rtx target, rtx src) } else { - rtx ops[] = {tmp, elt}; - emit_vlmax_insn (code_for_pred_broadcast (mode), UNARY_OP, ops); + /* Emit vec_duplicate<mode> split pattern before RA so that + we could have a better optimization opportunity in LICM + which will hoist vmv.v.x outside the loop and in fwprop && combine + which will transform 'vv' into 'vx' instruction. + + The reason we don't emit vec_duplicate<mode> split pattern during + RA since the split stage after RA is a too late stage to generate + RVV instruction which need an additional register (We can't + allocate a new register after RA) for VL operand of vsetvl + instruction (vsetvl a5, zero). */ + if (lra_in_progress) + { + rtx ops[] = {tmp, elt}; + emit_vlmax_insn (code_for_pred_broadcast (mode), UNARY_OP, ops); + } + else + { + struct expand_operand ops[2]; + enum insn_code icode = optab_handler (vec_duplicate_optab, mode); + gcc_assert (icode != CODE_FOR_nothing); + create_output_operand (&ops[0], tmp, mode); + create_input_operand (&ops[1], elt, GET_MODE_INNER (mode)); + expand_insn (icode, 2, ops); + tmp = ops[0].value; + } } if (tmp != target) diff --git a/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-7.c b/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-7.c index 3dfc6f16a25..2a735d8c6b6 100644 --- a/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-7.c +++ b/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-7.c @@ -18,7 +18,8 @@ bar (int *x, int a, int b, int n) } /* { dg-final { scan-assembler {e32,m2} } } */ -/* { dg-final { scan-assembler-times {csrr} 1 } } */ +/* { dg-final { scan-assembler-not {jr} } } */ +/* { dg-final { scan-assembler-times {ret} 2 } } * /* { dg-final { scan-tree-dump-times "Maximum lmul = 8" 1 "vect" } } */ /* { dg-final { scan-tree-dump-times "Maximum lmul = 4" 1 "vect" } } */ /* { dg-final { scan-tree-dump-times "Maximum lmul = 2" 1 "vect" } } */ diff --git a/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/pr111848.c b/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/pr111848.c new file mode 100644 index 00000000000..b203ca907fa --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/pr111848.c @@ -0,0 +1,35 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gcv -mabi=lp64d -fdump-tree-vect-details" } */ + +void +f3 (uint8_t *restrict a, uint8_t *restrict b, + uint8_t *restrict c, uint8_t *restrict d, + int n) +{ + for (int i = 0; i < n; ++i) + { + a[i * 8] = c[i * 8] + d[i * 8]; + a[i * 8 + 1] = c[i * 8] + d[i * 8 + 1]; + a[i * 8 + 2] = c[i * 8 + 2] + d[i * 8 + 2]; + a[i * 8 + 3] = c[i * 8 + 2] + d[i * 8 + 3]; + a[i * 8 + 4] = c[i * 8 + 4] + d[i * 8 + 4]; + a[i * 8 + 5] = c[i * 8 + 4] + d[i * 8 + 5]; + a[i * 8 + 6] = c[i * 8 + 6] + d[i * 8 + 6]; + a[i * 8 + 7] = c[i * 8 + 6] + d[i * 8 + 7]; + b[i * 8] = c[i * 8 + 1] + d[i * 8]; + b[i * 8 + 1] = c[i * 8 + 1] + d[i * 8 + 1]; + b[i * 8 + 2] = c[i * 8 + 3] + d[i * 8 + 2]; + b[i * 8 + 3] = c[i * 8 + 3] + d[i * 8 + 3]; + b[i * 8 + 4] = c[i * 8 + 5] + d[i * 8 + 4]; + b[i * 8 + 5] = c[i * 8 + 5] + d[i * 8 + 5]; + b[i * 8 + 6] = c[i * 8 + 7] + d[i * 8 + 6]; + b[i * 8 + 7] = c[i * 8 + 7] + d[i * 8 + 7]; + } +} + +/* { dg-final { scan-assembler {e8,m4} } } */ +/* { dg-final { scan-assembler-not {jr} } } */ +/* { dg-final { scan-assembler-times {ret} 1 } } * +/* { dg-final { scan-tree-dump-times "Maximum lmul = 4" 1 "vect" } } */ +/* { dg-final { scan-tree-dump-not "Maximum lmul = 2" "vect" } } */ +/* { dg-final { scan-tree-dump-not "Maximum lmul = 1" "vect" } } */ -- 2.36.3
