From 4796d8f620f4a2360e861f336073202c18e649fc Mon Sep 17 00:00:00 2001 From: Vladimir Makarov Date: Tue, 11 Apr 2017 19:39:59 +0000 Subject: [PATCH] re PR rtl-optimization/70478 ([LRA] S/390: Performance regression - superfluous stack frame) 2017-04-11 Vladimir Makarov PR rtl-optimization/70478 * lra-constraints.c (process_alt_operands): Check memory for disfavoring memory insn operand. From-SVN: r246854 --- gcc/ChangeLog | 6 ++++++ gcc/lra-constraints.c | 14 ++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index e5b4c75f380..11304c8e9c3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-04-11 Vladimir Makarov + + PR rtl-optimization/70478 + * lra-constraints.c (process_alt_operands): Check memory for + disfavoring memory insn operand. + 2017-04-11 Jakub Jelinek PR middle-end/80100 diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c index 82b1ed0d403..c8bc9b9a66f 100644 --- a/gcc/lra-constraints.c +++ b/gcc/lra-constraints.c @@ -2722,12 +2722,14 @@ 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) + /* When we use an operand requiring memory in given + alternative, the insn should write *and* read the + value to/from memory it is costly in comparison with + an insn alternative which does not use memory + (e.g. register or immediate operand). We exclude + memory operand for such case as we can satisfy the + memory constraints by reloading address. */ + if (no_regs_p && offmemok && !MEM_P (op)) { if (lra_dump_file != NULL) fprintf