diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 11 | ||||
| -rw-r--r-- | gcc/fold-const.c | 22 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr52578.c | 14 | ||||
| -rw-r--r-- | gcc/tree-ssa-forwprop.c | 9 |
5 files changed, 54 insertions, 7 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 88fc5425d95..4a3d0d12fe9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,14 @@ +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. + 2012-03-14 Uros Bizjak <ubizjak@gmail.com> Revert: 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; } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 11c8e8fa40a..b4626f3422e 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2012-03-14 Richard Guenther <rguenther@suse.de> + + PR middle-end/52578 + * gcc.dg/pr52578.c: New testcase. + 2012-03-14 Jakub Jelinek <jakub@redhat.com> PR c++/52521 diff --git a/gcc/testsuite/gcc.dg/pr52578.c b/gcc/testsuite/gcc.dg/pr52578.c new file mode 100644 index 00000000000..0e668300f20 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr52578.c @@ -0,0 +1,14 @@ +/* { dg-do compile } */ +/* { dg-options "-fdump-tree-original" } */ + +long bar (long i) +{ + return (long)((unsigned long)i + 2) - (long)i; +} +long foo (int i) +{ + return (long)((unsigned long)i + 2) - (long)i; +} + +/* { dg-final { scan-tree-dump-times "return 2;" 2 "original" } } */ +/* { dg-final { cleanup-tree-dump "original" } } */ diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c index 20821ef8b98..919779526d9 100644 --- a/gcc/tree-ssa-forwprop.c +++ b/gcc/tree-ssa-forwprop.c @@ -2285,10 +2285,13 @@ combine_conversions (gimple_stmt_iterator *gsi) } /* 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)) { gimple_assign_set_rhs1 (stmt, defop0); update_stmt (stmt); |