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| author | Eric Botcazou <ebotcazou@gcc.gnu.org> | 2017-10-25 21:53:21 +0000 |
|---|---|---|
| committer | Eric Botcazou <ebotcazou@gcc.gnu.org> | 2017-10-25 21:53:21 +0000 |
| commit | c0b24017eb8fee727bf1244e269e4b6b435e7952 (patch) | |
| tree | d798c4a380498017a30d56af6f0e4f30dd6187b1 /gcc/fold-const.c | |
| parent | a2af967e9718d3d15461dbc5c52008ceab63a2f0 (diff) | |
| download | gcc-c0b24017eb8fee727bf1244e269e4b6b435e7952.zip gcc-c0b24017eb8fee727bf1244e269e4b6b435e7952.tar.gz gcc-c0b24017eb8fee727bf1244e269e4b6b435e7952.tar.bz2 | |
re PR middle-end/82062 (simple conditional expressions no longer folded)
PR middle-end/82062
* fold-const.c (operand_equal_for_comparison_p): Also return true
if ARG0 is a simple variant of ARG1 with narrower precision.
(fold_ternary_loc): Always pass unstripped operands to the predicate.
From-SVN: r254089
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index c16959b..9db5aeb 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3366,7 +3366,8 @@ operand_equal_p (const_tree arg0, const_tree arg1, unsigned int flags) #undef OP_SAME_WITH_NULL } -/* Similar to operand_equal_p, but strip nops first. */ +/* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1 + with a different signedness or a narrower precision. */ static bool operand_equal_for_comparison_p (tree arg0, tree arg1) @@ -3381,9 +3382,20 @@ operand_equal_for_comparison_p (tree arg0, tree arg1) /* Discard any conversions that don't change the modes of ARG0 and ARG1 and see if the inner values are the same. This removes any signedness comparison, which doesn't matter here. */ - STRIP_NOPS (arg0); - STRIP_NOPS (arg1); - if (operand_equal_p (arg0, arg1, 0)) + tree op0 = arg0; + tree op1 = arg1; + STRIP_NOPS (op0); + STRIP_NOPS (op1); + if (operand_equal_p (op0, op1, 0)) + return true; + + /* Discard a single widening conversion from ARG1 and see if the inner + value is the same as ARG0. */ + if (CONVERT_EXPR_P (arg1) + && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (arg1, 0))) + && TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0))) + < TYPE_PRECISION (TREE_TYPE (arg1)) + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) return true; return false; @@ -11169,8 +11181,8 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type, Also try swapping the arguments and inverting the conditional. */ if (COMPARISON_CLASS_P (arg0) - && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), arg1) - && !HONOR_SIGNED_ZEROS (element_mode (arg1))) + && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), op1) + && !HONOR_SIGNED_ZEROS (element_mode (op1))) { tem = fold_cond_expr_with_comparison (loc, type, arg0, op1, op2); if (tem) |