diff options
| author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2012-03-14 10:51:34 +0000 |
|---|---|---|
| committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2012-03-14 10:51:34 +0000 |
| commit | a6476f88a046784b087cee7ea22806cf181d073d (patch) | |
| tree | 66df900ef28ae410bf4318c9859d7595727e851a /gcc/fold-const.c | |
| parent | 6281b3df10b5122d3520683874bd53b73c69975d (diff) | |
| download | gcc-a6476f88a046784b087cee7ea22806cf181d073d.tar.gz | |
2012-03-14 Richard Guenther <rguenther@suse.de>
PR middle-end/52578
* fold-const.c (fold_unary_loc): Fold (T1)(T2)x to (T1)x if
the outermost conversion is a sign-change only.
(fold_binary_loc): Disregard widening and sign-changing
conversions when we determine if two variables are equal
for reassociation.
* tree-ssa-forwprop.c (combine_conversions): Fold (T1)(T2)x to
(T1)x if the outermost conversion is a sign-change only.
* gcc.dg/pr52578.c: New testcase.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@185378 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index ab653ea074b..9f5c0971761 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -7843,10 +7843,13 @@ fold_unary_loc (location_t loc, enum tree_code code, tree type, tree op0) return fold_build1_loc (loc, code, type, TREE_OPERAND (op0, 0)); /* If we have a sign-extension of a zero-extended value, we can - replace that by a single zero-extension. */ + replace that by a single zero-extension. Likewise if the + final conversion does not change precision we can drop the + intermediate conversion. */ if (inside_int && inter_int && final_int - && inside_prec < inter_prec && inter_prec < final_prec - && inside_unsignedp && !inter_unsignedp) + && ((inside_prec < inter_prec && inter_prec < final_prec + && inside_unsignedp && !inter_unsignedp) + || final_prec == inter_prec)) return fold_build1_loc (loc, code, type, TREE_OPERAND (op0, 0)); /* Two conversions in a row are not needed unless: @@ -10335,10 +10338,21 @@ fold_binary_loc (location_t loc, if (TREE_CODE (tmp0) == NEGATE_EXPR) tmp0 = TREE_OPERAND (tmp0, 0); + if (CONVERT_EXPR_P (tmp0) + && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (tmp0, 0))) + && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (tmp0, 0))) + <= TYPE_PRECISION (type))) + tmp0 = TREE_OPERAND (tmp0, 0); if (TREE_CODE (tmp1) == NEGATE_EXPR) tmp1 = TREE_OPERAND (tmp1, 0); + if (CONVERT_EXPR_P (tmp1) + && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (tmp1, 0))) + && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (tmp1, 0))) + <= TYPE_PRECISION (type))) + tmp1 = TREE_OPERAND (tmp1, 0); /* The only case we can still associate with two variables - is if they are the same, modulo negation. */ + is if they are the same, modulo negation and bit-pattern + preserving conversions. */ if (!operand_equal_p (tmp0, tmp1, 0)) ok = false; } |