From ac684a206cf3b8708d77398bebe76fb63308e88c Mon Sep 17 00:00:00 2001 From: Jeff Law Date: Tue, 4 Feb 1997 16:36:26 -0700 Subject: [PATCH] flow.c (life_analysis): Delete obvious no-op moves which use SUBREGs. * flow.c (life_analysis): Delete obvious no-op moves which use SUBREGs. From-SVN: r13607 --- gcc/flow.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/gcc/flow.c b/gcc/flow.c index 75948c562bdd..72b42ead9b31 100644 --- a/gcc/flow.c +++ b/gcc/flow.c @@ -996,6 +996,23 @@ life_analysis (f, nregs) NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; NOTE_SOURCE_FILE (insn) = 0; } + /* Delete (in effect) any obvious no-op moves. */ + else if (GET_CODE (PATTERN (insn)) == SET + && GET_CODE (SET_DEST (PATTERN (insn))) == SUBREG + && GET_CODE (SUBREG_REG (SET_DEST (PATTERN (insn)))) == REG + && GET_CODE (SET_SRC (PATTERN (insn))) == SUBREG + && GET_CODE (SUBREG_REG (SET_SRC (PATTERN (insn)))) == REG + && REGNO (SUBREG_REG (SET_DEST (PATTERN (insn)))) == + REGNO (SUBREG_REG (SET_SRC (PATTERN (insn)))) + && SUBREG_WORD (SET_DEST (PATTERN (insn))) == + SUBREG_WORD (SET_SRC (PATTERN (insn))) + /* Insns carrying these notes are useful later on. */ + && ! find_reg_note (insn, REG_EQUAL, NULL_RTX)) + { + PUT_CODE (insn, NOTE); + NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; + NOTE_SOURCE_FILE (insn) = 0; + } else if (GET_CODE (PATTERN (insn)) == PARALLEL) { /* If nothing but SETs of registers to themselves,