From 14895892092af3b7bcddde60e14aaf0472fb7903 Mon Sep 17 00:00:00 2001 From: amodra Date: Tue, 3 May 2016 14:43:35 +0000 Subject: [PATCH] PR70890, stage2 miscompilation PR rtl-optimization/70890 * ira.c (combine_and_move_insns): When moving def_insn, remove equivs on use_insn. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@235825 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 6 ++++++ gcc/ira.c | 16 ++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 095e502adfa4..7cd0bd4f73de 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2016-05-03 Alan Modra + + PR rtl-optimization/70890 + * ira.c (combine_and_move_insns): When moving def_insn, remove + equivs on use_insn. + 2016-05-03 Dominik Vogt * config/s390/s390.md ("*rsbg__sll") diff --git a/gcc/ira.c b/gcc/ira.c index d383a5513705..55b4bd700be8 100644 --- a/gcc/ira.c +++ b/gcc/ira.c @@ -3742,6 +3742,22 @@ combine_and_move_insns (void) if (use_insn == BB_HEAD (use_bb)) BB_HEAD (use_bb) = new_insn; + /* We know regno dies in use_insn, but inside a loop + REG_DEAD notes might be missing when def_insn was in + another basic block. However, when we move def_insn into + this bb we'll definitely get a REG_DEAD note and reload + will see the death. It's possible that update_equiv_regs + set up an equivalence referencing regno for a reg set by + use_insn, when regno was seen as non-local. Now that + regno is local to this block, and dies, such an + equivalence is invalid. */ + if (find_reg_note (use_insn, REG_EQUIV, NULL_RTX)) + { + rtx set = single_set (use_insn); + if (set && REG_P (SET_DEST (set))) + no_equiv (SET_DEST (set), set, NULL); + } + ira_reg_equiv[regno].init_insns = gen_rtx_INSN_LIST (VOIDmode, new_insn, NULL_RTX); bitmap_set_bit (cleared_regs, regno); -- 2.47.3