From 26bd2dab50817184b73cea1034d7e60d55def70d Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Sat, 26 Oct 2019 18:38:59 +0200 Subject: [PATCH] rs6000: Fix allocate_stack in a corner case (PR91289) When we have -fstack-limit-symbol with sysv we can end up with a non- existing instruction (you cannot add an immediate to register 0). Fix this by using register 11 instead. It might be used for something else already though, so save and restore its value around this. In optimizing compiles these extra moves are usually removed again: the restore by cprop_hardreg, and then the save by rtl_dce. PR target/91289 * config/rs6000/rs6000-logue.c (rs6000_emit_allocate_stack): Don't add an immediate to r0; use r11 instead. Save and restore r11 to r0 around this. From-SVN: r277472 --- gcc/ChangeLog | 7 +++++++ gcc/config/rs6000/rs6000-logue.c | 12 ++++++++---- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3dc1b7c08a3..de55e1a8323 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2019-10-26 Segher Boessenkool + + PR target/91289 + * config/rs6000/rs6000-logue.c (rs6000_emit_allocate_stack): Don't add + an immediate to r0; use r11 instead. Save and restore r11 to r0 around + this. + 2019-10-26 Hongtao Liu * config/i386/sse.md diff --git a/gcc/config/rs6000/rs6000-logue.c b/gcc/config/rs6000/rs6000-logue.c index e98893a440c..04aae8052db 100644 --- a/gcc/config/rs6000/rs6000-logue.c +++ b/gcc/config/rs6000/rs6000-logue.c @@ -1700,10 +1700,14 @@ rs6000_emit_allocate_stack (HOST_WIDE_INT size, rtx copy_reg, int copy_off) stack_limit_rtx, GEN_INT (size))); - emit_insn (gen_elf_high (tmp_reg, toload)); - emit_insn (gen_elf_low (tmp_reg, tmp_reg, toload)); - emit_insn (gen_cond_trap (LTU, stack_reg, tmp_reg, - const0_rtx)); + /* We cannot use r0 with elf_low. Lamely solve this problem by + moving registers around. */ + rtx r11_reg = gen_rtx_REG (Pmode, 11); + emit_move_insn (tmp_reg, r11_reg); + emit_insn (gen_elf_high (r11_reg, toload)); + emit_insn (gen_elf_low (r11_reg, r11_reg, toload)); + emit_insn (gen_cond_trap (LTU, stack_reg, r11_reg, const0_rtx)); + emit_move_insn (r11_reg, tmp_reg); } else warning (0, "stack limit expression is not supported"); -- 2.30.2