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| author | Paolo Bonzini <bonzini@gnu.org> | 2005-11-24 09:47:36 +0000 |
|---|---|---|
| committer | Paolo Bonzini <bonzini@gcc.gnu.org> | 2005-11-24 09:47:36 +0000 |
| commit | 9063128058ba5d3323a02f897f75c8818863430d (patch) | |
| tree | 3717e20b6ad857a72b3d06979afc1fdffaf8a953 /gcc | |
| parent | 9df540a8d941d18ea691c3eba9a09d12107d5c3e (diff) | |
| download | gcc-9063128058ba5d3323a02f897f75c8818863430d.zip gcc-9063128058ba5d3323a02f897f75c8818863430d.tar.gz gcc-9063128058ba5d3323a02f897f75c8818863430d.tar.bz2 | |
gcse.c (hash_scan_set): Look through REG_EQUAL or REG_EQUIV notes also when doing PRE...
2005-11-24 Paolo Bonzini <bonzini@gnu.org>
* gcse.c (hash_scan_set): Look through REG_EQUAL or REG_EQUIV notes
also when doing PRE, rather than only for global CPROP.
From-SVN: r107456
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/gcse.c | 16 |
2 files changed, 15 insertions, 6 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 67e050a..361250d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2005-11-24 Paolo Bonzini <bonzini@gnu.org> + + * gcse.c (hash_scan_set): Look through REG_EQUAL or REG_EQUIV notes + also when doing PRE, rather than only for global CPROP. + 2005-11-24 Ben Elliston <bje@au.ibm.com> * machmode.h (CLASS_HAS_WIDER_MODES_P): New macro. @@ -1700,10 +1700,15 @@ hash_scan_set (rtx pat, rtx insn, struct hash_table *table) unsigned int regno = REGNO (dest); rtx tmp; - /* If this is a single set and we are doing constant propagation, - see if a REG_NOTE shows this equivalent to a constant. */ - if (table->set_p && (note = find_reg_equal_equiv_note (insn)) != 0 - && gcse_constant_p (XEXP (note, 0))) + /* See if a REG_NOTE shows this equivalent to a simpler expression. + This allows us to do a single GCSE pass and still eliminate + redundant constants, addresses or other expressions that are + constructed with multiple instructions. */ + note = find_reg_equal_equiv_note (insn); + if (note != 0 + && (table->set_p + ? gcse_constant_p (XEXP (note, 0)) + : want_to_gcse_p (XEXP (note, 0)))) src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src); /* Only record sets of pseudo-regs in the hash table. */ @@ -1724,8 +1729,7 @@ hash_scan_set (rtx pat, rtx insn, struct hash_table *table) REG_EQUIV notes and if the argument slot is used somewhere explicitly, it means address of parameter has been taken, so we should not extend the lifetime of the pseudo. */ - && ((note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) == 0 - || ! MEM_P (XEXP (note, 0)))) + && (note == NULL_RTX || ! MEM_P (XEXP (note, 0)))) { /* An expression is not anticipatable if its operands are modified before this insn or if this is not the only SET in |