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| author | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 1998-09-20 00:01:31 +0000 |
|---|---|---|
| committer | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 1998-09-20 00:01:31 +0000 |
| commit | 89a9144c1493b59daa8bc2e150ab9a38fb919b01 (patch) | |
| tree | c94d12e5ec3fecf3937f1e0686b63e8510af6e51 /gcc/combine.c | |
| parent | b3744b6b4edf4790eb8d69e25eb29f867c3acc5a (diff) | |
| download | gcc-89a9144c1493b59daa8bc2e150ab9a38fb919b01.tar.gz | |
* combine.c (distribute_notes): If an insn is a cc0 user, only
delete it if we can also delete the cc0 setter.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@22489 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 024cb51e48b..e2a0095a1db 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -11542,6 +11542,7 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1) { rtx set = single_set (tem); rtx inner_dest = 0; + rtx cc0_setter = NULL_RTX; if (set != 0) for (inner_dest = SET_DEST (set); @@ -11552,10 +11553,21 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1) ; /* Verify that it was the set, and not a clobber that - modified the register. */ + modified the register. + + CC0 targets must be careful to maintain setter/user + pairs. If we cannot delete the setter due to side + effects, mark the user with an UNUSED note instead + of deleting it. */ if (set != 0 && ! side_effects_p (SET_SRC (set)) - && rtx_equal_p (XEXP (note, 0), inner_dest)) + && rtx_equal_p (XEXP (note, 0), inner_dest) +#ifdef HAVE_cc0 + && (! reg_mentioned_p (cc0_rtx, SET_SRC (set)) + || ((cc0_setter = prev_cc0_setter (tem)) != NULL + && sets_cc0_p (PATTERN (cc0_setter)) > 0)) +#endif + ) { /* Move the notes and links of TEM elsewhere. This might delete other dead insns recursively. @@ -11571,6 +11583,23 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1) PUT_CODE (tem, NOTE); NOTE_LINE_NUMBER (tem) = NOTE_INSN_DELETED; NOTE_SOURCE_FILE (tem) = 0; + +#ifdef HAVE_cc0 + /* Delete the setter too. */ + if (cc0_setter) + { + PATTERN (cc0_setter) = pc_rtx; + + distribute_notes (REG_NOTES (cc0_setter), + cc0_setter, cc0_setter, + NULL_RTX, NULL_RTX, NULL_RTX); + distribute_links (LOG_LINKS (cc0_setter)); + + PUT_CODE (cc0_setter, NOTE); + NOTE_LINE_NUMBER (cc0_setter) = NOTE_INSN_DELETED; + NOTE_SOURCE_FILE (cc0_setter) = 0; + } +#endif } /* If the register is both set and used here, put the REG_DEAD note here, but place a REG_UNUSED note |