From 688703569091edfd0400523d85cbb44d15aa61ea Mon Sep 17 00:00:00 2001 From: "Vladimir N. Makarov" Date: Mon, 28 Feb 2022 16:43:50 -0500 Subject: [PATCH] [PR104637] LRA: Split hard regs as many as possible on one subpass LRA hard reg split subpass is a small subpass used as the last resort for LRA when it can not assign a hard reg to a reload pseudo by other ways (e.g. by spilling non-reload pseudos). For simplicity the subpass works on one split base (as each split changes pseudo live range info). In this case it results in reaching maximal possible number of subpasses. The patch implements as many non-overlapping hard reg splits splits as possible on each subpass. gcc/ChangeLog: PR rtl-optimization/104637 * lra-assigns.c (lra_split_hard_reg_for): Split hard regs as many as possible on one subpass. gcc/testsuite/ChangeLog: PR rtl-optimization/104637 * gcc.target/i386/pr104637.c: New. --- gcc/lra-assigns.c | 41 ++++++++++++++++++++---- gcc/testsuite/gcc.target/i386/pr104637.c | 22 +++++++++++++ 2 files changed, 57 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr104637.c diff --git a/gcc/lra-assigns.c b/gcc/lra-assigns.c index 40e323c2a647..c280775333f0 100644 --- a/gcc/lra-assigns.c +++ b/gcc/lra-assigns.c @@ -1773,8 +1773,8 @@ lra_split_hard_reg_for (void) iterations. Either it's an asm and something is wrong with the constraints, or we have run out of spill registers; error out in either case. */ - bool asm_p = false; - bitmap_head failed_reload_insns, failed_reload_pseudos; + bool asm_p = false, spill_p = false; + bitmap_head failed_reload_insns, failed_reload_pseudos, over_split_insns; if (lra_dump_file != NULL) fprintf (lra_dump_file, @@ -1785,6 +1785,7 @@ lra_split_hard_reg_for (void) bitmap_ior (&non_reload_pseudos, &lra_inheritance_pseudos, &lra_split_regs); bitmap_ior_into (&non_reload_pseudos, &lra_subreg_reload_pseudos); bitmap_ior_into (&non_reload_pseudos, &lra_optional_reload_pseudos); + bitmap_initialize (&over_split_insns, ®_obstack); for (i = lra_constraint_new_regno_start; i < max_regno; i++) if (reg_renumber[i] < 0 && lra_reg_info[i].nrefs != 0 && (rclass = lra_get_allocno_class (i)) != NO_REGS @@ -1792,13 +1793,41 @@ lra_split_hard_reg_for (void) { if (! find_reload_regno_insns (i, first, last)) continue; - if (spill_hard_reg_in_range (i, rclass, first, last)) + if (BLOCK_FOR_INSN (first) == BLOCK_FOR_INSN (last)) { - bitmap_clear (&failed_reload_pseudos); - return true; + /* Check that we are not trying to split over the same insn + requiring reloads to avoid splitting the same hard reg twice or + more. If we need several hard regs splitting over the same insn + it can be finished on the next iterations. + + The following loop iteration number is small as we split hard + reg in a very small range. */ + for (insn = first; + insn != NEXT_INSN (last); + insn = NEXT_INSN (insn)) + if (bitmap_bit_p (&over_split_insns, INSN_UID (insn))) + break; + if (insn != NEXT_INSN (last) + || !spill_hard_reg_in_range (i, rclass, first, last)) + { + bitmap_set_bit (&failed_reload_pseudos, i); + } + else + { + for (insn = first; + insn != NEXT_INSN (last); + insn = NEXT_INSN (insn)) + bitmap_set_bit (&over_split_insns, INSN_UID (insn)); + spill_p = true; + } } - bitmap_set_bit (&failed_reload_pseudos, i); } + bitmap_clear (&over_split_insns); + if (spill_p) + { + bitmap_clear (&failed_reload_pseudos); + return true; + } bitmap_clear (&non_reload_pseudos); bitmap_initialize (&failed_reload_insns, ®_obstack); EXECUTE_IF_SET_IN_BITMAP (&failed_reload_pseudos, 0, u, bi) diff --git a/gcc/testsuite/gcc.target/i386/pr104637.c b/gcc/testsuite/gcc.target/i386/pr104637.c new file mode 100644 index 000000000000..65e8635d55e7 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr104637.c @@ -0,0 +1,22 @@ +/* { dg-do compile } */ +/* { dg-options "-Og -fno-forward-propagate -mavx" } */ + +typedef short __attribute__((__vector_size__ (64))) U; +typedef unsigned long long __attribute__((__vector_size__ (32))) V; +typedef long double __attribute__((__vector_size__ (64))) F; + +int i; +U u; +F f; + +void +foo (char a, char b, _Complex char c, V v) +{ + u = (U) { u[0] / 0, u[1] / 0, u[2] / 0, u[3] / 0, u[4] / 0, u[5] / 0, u[6] / 0, u[7] / 0, + u[8] / 0, u[0] / 0, u[9] / 0, u[10] / 0, u[11] / 0, u[12] / 0, u[13] / 0, u[14] / 0, u[15] / 0, + u[16] / 0, u[17] / 0, u[18] / 0, u[19] / 0, u[20] / 0, u[21] / 0, u[22] / 0, u[23] / 0, + u[24] / 0, u[25] / 0, u[26] / 0, u[27] / 0, u[28] / 0, u[29] / 0, u[30] / 0, u[31] / 0 }; + c += i; + f = (F) { v[0], v[1], v[2], v[3] }; + i = (char) (__imag__ c + i); +} -- 2.47.2