As testcase in the PR, O3 cunrolli may prevent vectorization for the innermost loop and increase register pressure. The patch removes the 1/3 reduction of unr_insn for innermost loop for UL_ALL. ul != UR_ALL is needed since some small loop complete unrolling at O2 relies the reduction.
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}. No big impact for SPEC2017. Ok for trunk? gcc/ChangeLog: PR tree-optimization/112325 * tree-ssa-loop-ivcanon.cc (estimated_unrolled_size): Add 2 new parameters: loop and ul, and remove unr_insns reduction for innermost loop. (try_unroll_loop_completely): Pass loop and ul to estimated_unrolled_size. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/pr112325.c: New test. * gcc.dg/vect/pr69783.c: Add extra option --param max-completely-peeled-insns=300. --- gcc/testsuite/gcc.dg/tree-ssa/pr112325.c | 57 ++++++++++++++++++++++++ gcc/testsuite/gcc.dg/vect/pr69783.c | 2 +- gcc/tree-ssa-loop-ivcanon.cc | 16 +++++-- 3 files changed, 71 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr112325.c diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr112325.c b/gcc/testsuite/gcc.dg/tree-ssa/pr112325.c new file mode 100644 index 00000000000..14208b3e7f8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr112325.c @@ -0,0 +1,57 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-cunrolli-details" } */ + +typedef unsigned short ggml_fp16_t; +static float table_f32_f16[1 << 16]; + +inline static float ggml_lookup_fp16_to_fp32(ggml_fp16_t f) { + unsigned short s; + __builtin_memcpy(&s, &f, sizeof(unsigned short)); + return table_f32_f16[s]; +} + +typedef struct { + ggml_fp16_t d; + ggml_fp16_t m; + unsigned char qh[4]; + unsigned char qs[32 / 2]; +} block_q5_1; + +typedef struct { + float d; + float s; + char qs[32]; +} block_q8_1; + +void ggml_vec_dot_q5_1_q8_1(const int n, float * restrict s, const void * restrict vx, const void * restrict vy) { + const int qk = 32; + const int nb = n / qk; + + const block_q5_1 * restrict x = vx; + const block_q8_1 * restrict y = vy; + + float sumf = 0.0; + + for (int i = 0; i < nb; i++) { + unsigned qh; + __builtin_memcpy(&qh, x[i].qh, sizeof(qh)); + + int sumi = 0; + + for (int j = 0; j < qk/2; ++j) { + const unsigned char xh_0 = ((qh >> (j + 0)) << 4) & 0x10; + const unsigned char xh_1 = ((qh >> (j + 12)) ) & 0x10; + + const int x0 = (x[i].qs[j] & 0xF) | xh_0; + const int x1 = (x[i].qs[j] >> 4) | xh_1; + + sumi += (x0 * y[i].qs[j]) + (x1 * y[i].qs[j + qk/2]); + } + + sumf += (ggml_lookup_fp16_to_fp32(x[i].d)*y[i].d)*sumi + ggml_lookup_fp16_to_fp32(x[i].m)*y[i].s; + } + + *s = sumf; +} + +/* { dg-final { scan-tree-dump {(?n)Not unrolling loop [1-9] \(--param max-completely-peel-times limit reached} "cunrolli"} } */ diff --git a/gcc/testsuite/gcc.dg/vect/pr69783.c b/gcc/testsuite/gcc.dg/vect/pr69783.c index 5df95d0ce4e..a1f75514d72 100644 --- a/gcc/testsuite/gcc.dg/vect/pr69783.c +++ b/gcc/testsuite/gcc.dg/vect/pr69783.c @@ -1,6 +1,6 @@ /* { dg-do compile } */ /* { dg-require-effective-target vect_float } */ -/* { dg-additional-options "-Ofast -funroll-loops" } */ +/* { dg-additional-options "-Ofast -funroll-loops --param max-completely-peeled-insns=300" } */ #define NXX 516 #define NYY 516 diff --git a/gcc/tree-ssa-loop-ivcanon.cc b/gcc/tree-ssa-loop-ivcanon.cc index bf017137260..5e0eca647a1 100644 --- a/gcc/tree-ssa-loop-ivcanon.cc +++ b/gcc/tree-ssa-loop-ivcanon.cc @@ -444,7 +444,9 @@ tree_estimate_loop_size (class loop *loop, edge exit, edge edge_to_cancel, static unsigned HOST_WIDE_INT estimated_unrolled_size (struct loop_size *size, - unsigned HOST_WIDE_INT nunroll) + unsigned HOST_WIDE_INT nunroll, + enum unroll_level ul, + class loop* loop) { HOST_WIDE_INT unr_insns = ((nunroll) * (HOST_WIDE_INT) (size->overall @@ -453,7 +455,15 @@ estimated_unrolled_size (struct loop_size *size, unr_insns = 0; unr_insns += size->last_iteration - size->last_iteration_eliminated_by_peeling; - unr_insns = unr_insns * 2 / 3; + /* For innermost loop, loop body is not likely to be simplied as much as 1/3. + and may increase a lot of register pressure. + UL != UL_ALL is need to unroll small loop at O2. */ + class loop *loop_father = loop_outer (loop); + if (loop->inner || !loop_father + || loop_father->latch == EXIT_BLOCK_PTR_FOR_FN (cfun) + || ul != UL_ALL) + unr_insns = unr_insns * 2 / 3; + if (unr_insns <= 0) unr_insns = 1; @@ -837,7 +847,7 @@ try_unroll_loop_completely (class loop *loop, unsigned HOST_WIDE_INT ninsns = size.overall; unsigned HOST_WIDE_INT unr_insns - = estimated_unrolled_size (&size, n_unroll); + = estimated_unrolled_size (&size, n_unroll, ul, loop); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, " Loop size: %d\n", (int) ninsns); -- 2.31.1