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| author | law <law@138bc75d-0d04-0410-961f-82ee72b054a4> | 1997-02-04 23:36:26 +0000 |
|---|---|---|
| committer | law <law@138bc75d-0d04-0410-961f-82ee72b054a4> | 1997-02-04 23:36:26 +0000 |
| commit | da8cdbc4e6cf6d91e166f309c612174a44f1be21 (patch) | |
| tree | 44dce3a6399d68d0be62b88f643dfaf434e780f3 /gcc/flow.c | |
| parent | bfa1089d3d0c822449d6da40b619455914748c5b (diff) | |
| download | gcc-da8cdbc4e6cf6d91e166f309c612174a44f1be21.tar.gz | |
* flow.c (life_analysis): Delete obvious no-op moves
which use SUBREGs.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@13607 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/flow.c')
| -rw-r--r-- | gcc/flow.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/gcc/flow.c b/gcc/flow.c index 75948c562bd..72b42ead9b3 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, |