From 9b195552ab86ef09b69ddcd3c2243c166c4a8558 Mon Sep 17 00:00:00 2001 From: Vladimir Makarov Date: Mon, 10 Apr 2017 14:58:33 +0000 Subject: [PATCH] re PR rtl-optimization/70478 ([LRA] S/390: Performance regression - superfluous stack frame) 2017-04-10 Vladimir Makarov PR rtl-optimization/70478 * lra-constraints.c (curr_small_class_check): New. (update_and_check_small_class_inputs): New. (process_alt_operands): Update curr_small_class_check. Disfavor alternative insn memory operands. Check available regs for small class operands. From-SVN: r246808 --- gcc/ChangeLog | 9 ++++++++ gcc/lra-constraints.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 69 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index bf3119a..00b994b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2017-04-10 Vladimir Makarov + + PR rtl-optimization/70478 + * lra-constraints.c (curr_small_class_check): New. + (update_and_check_small_class_inputs): New. + (process_alt_operands): Update curr_small_class_check. Disfavor + alternative insn memory operands. Check available regs for small + class operands. + 2017-03-31 Matthew Fortune PR target/80057 diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c index 4d98624..82b1ed0 100644 --- a/gcc/lra-constraints.c +++ b/gcc/lra-constraints.c @@ -1852,6 +1852,42 @@ prohibited_class_reg_set_mode_p (enum reg_class rclass, (temp, ira_prohibited_class_mode_regs[rclass][mode])); } + +/* Used to check validity info about small class input operands. It + should be incremented at start of processing an insn + alternative. */ +static unsigned int curr_small_class_check = 0; + +/* Update number of used inputs of class OP_CLASS for operand NOP. + Return true if we have more such class operands than the number of + available regs. */ +static bool +update_and_check_small_class_inputs (int nop, enum reg_class op_class) +{ + static unsigned int small_class_check[LIM_REG_CLASSES]; + static int small_class_input_nums[LIM_REG_CLASSES]; + + if (SMALL_REGISTER_CLASS_P (op_class) + /* We are interesting in classes became small because of fixing + some hard regs, e.g. by an user through GCC options. */ + && hard_reg_set_intersect_p (reg_class_contents[op_class], + ira_no_alloc_regs) + && (curr_static_id->operand[nop].type != OP_OUT + || curr_static_id->operand[nop].early_clobber)) + { + if (small_class_check[op_class] == curr_small_class_check) + small_class_input_nums[op_class]++; + else + { + small_class_check[op_class] = curr_small_class_check; + small_class_input_nums[op_class] = 1; + } + if (small_class_input_nums[op_class] > ira_class_hard_regs_num[op_class]) + return true; + } + return false; +} + /* Major function to choose the current insn alternative and what operands should be reloaded and how. If ONLY_ALTERNATIVE is not negative we should consider only this alternative. Return false if @@ -1952,6 +1988,7 @@ process_alt_operands (int only_alternative) if (!TEST_BIT (preferred, nalt)) continue; + curr_small_class_check++; overall = losers = addr_losers = 0; static_reject = reject = reload_nregs = reload_sum = 0; for (nop = 0; nop < n_operands; nop++) @@ -2685,6 +2722,21 @@ process_alt_operands (int only_alternative) } } + /* When we use memory operand, the insn should read the + value from memory and even if we just wrote a value + into the memory it is costly in comparison with an + insn alternative which does not use memory + (e.g. register or immediate operand). */ + if (no_regs_p && offmemok) + { + if (lra_dump_file != NULL) + fprintf + (lra_dump_file, + " Using memory insn operand %d: reject+=3\n", + nop); + reject += 3; + } + #ifdef SECONDARY_MEMORY_NEEDED /* If reload requires moving value through secondary memory, it will need one more insn at least. */ @@ -2747,6 +2799,14 @@ process_alt_operands (int only_alternative) goto fail; } + if (update_and_check_small_class_inputs (nop, this_alternative)) + { + if (lra_dump_file != NULL) + fprintf (lra_dump_file, + " alt=%d, not enough small class regs -- refuse\n", + nalt); + goto fail; + } curr_alt[nop] = this_alternative; COPY_HARD_REG_SET (curr_alt_set[nop], this_alternative_set); curr_alt_win[nop] = this_alternative_win; -- 2.7.4