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| author | Richard Guenther <rguenther@suse.de> | 2009-01-07 10:53:30 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2009-01-07 10:53:30 +0000 |
| commit | cef158f9253739ab1b1f4342d530b933f1e1fc34 (patch) | |
| tree | 518bb42576e6930222440ecd11448fd0360f85b9 | |
| parent | 238e3a40af2349190dc662aed9476576af4b4516 (diff) | |
| download | gcc-cef158f9253739ab1b1f4342d530b933f1e1fc34.zip gcc-cef158f9253739ab1b1f4342d530b933f1e1fc34.tar.gz gcc-cef158f9253739ab1b1f4342d530b933f1e1fc34.tar.bz2 | |
re PR middle-end/38751 (odd performance regression with -Os)
2009-01-07 Richard Guenther <rguenther@suse.de>
PR middle-end/38751
* fold-const.c (extract_muldiv): Remove obsolete comment.
(fold_plusminus_mult_expr): Undo MINUS_EXPR
to PLUS_EXPR canonicalization for the canonicalization.
From-SVN: r143152
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/fold-const.c | 16 |
2 files changed, 18 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a8a606a..81804116 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2009-01-07 Richard Guenther <rguenther@suse.de> + + PR middle-end/38751 + * fold-const.c (extract_muldiv): Remove obsolete comment. + (fold_plusminus_mult_expr): Undo MINUS_EXPR + to PLUS_EXPR canonicalization for the canonicalization. + 2009-01-07 Gerald Pfeifer <gerald@pfeifer.com> * doc/install.texi (alpha*-dec-osf*): Remove note on 32-bit diff --git a/gcc/fold-const.c b/gcc/fold-const.c index be542b7..9b4106b 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -6008,10 +6008,6 @@ optimize_minmax_comparison (enum tree_code code, tree type, tree op0, tree op1) expression would not overflow or that overflow is undefined for the type in the language in question. - We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either - the machine has a multiply-accumulate insn or that this is part of an - addressing calculation. - If we return a non-null expression, it is an equivalent form of the original computation, but need not be in the original type. @@ -7439,7 +7435,17 @@ fold_plusminus_mult_expr (enum tree_code code, tree type, tree arg0, tree arg1) else if (TREE_CODE (arg1) == INTEGER_CST) { arg10 = build_one_cst (type); - arg11 = arg1; + /* As we canonicalize A - 2 to A + -2 get rid of that sign for + the purpose of this canonicalization. */ + if (TREE_INT_CST_HIGH (arg1) == -1 + && negate_expr_p (arg1) + && code == PLUS_EXPR) + { + arg11 = negate_expr (arg1); + code = MINUS_EXPR; + } + else + arg11 = arg1; } else { |