re PR tree-optimization/57656 (Wrong constant folding)
2013-09-03 Richard Biener <rguenther@suse.de> PR middle-end/57656 * fold-const.c (negate_expr_p): Fix division case. (negate_expr): Likewise. * gcc.dg/torture/pr57656.c: New testcase. From-SVN: r202204
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2013-09-03 Richard Biener <rguenther@suse.de>
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PR middle-end/57656
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* fold-const.c (negate_expr_p): Fix division case.
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(negate_expr): Likewise.
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2013-09-03 Richard Biener <rguenther@suse.de>
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2013-09-03 Richard Biener <rguenther@suse.de>
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PR lto/58285
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PR lto/58285
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@ -483,11 +483,24 @@ negate_expr_p (tree t)
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and actually traps on some architectures. But if overflow is
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and actually traps on some architectures. But if overflow is
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undefined, we can negate, because - (INT_MIN / 1) is an
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undefined, we can negate, because - (INT_MIN / 1) is an
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overflow. */
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overflow. */
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if (INTEGRAL_TYPE_P (TREE_TYPE (t))
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if (INTEGRAL_TYPE_P (TREE_TYPE (t)))
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&& !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (t)))
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{
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break;
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if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (t)))
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return negate_expr_p (TREE_OPERAND (t, 1))
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break;
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|| negate_expr_p (TREE_OPERAND (t, 0));
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/* If overflow is undefined then we have to be careful because
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we ask whether it's ok to associate the negate with the
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division which is not ok for example for
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-((a - b) / c) where (-(a - b)) / c may invoke undefined
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overflow because of negating INT_MIN. So do not use
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negate_expr_p here but open-code the two important cases. */
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if (TREE_CODE (TREE_OPERAND (t, 0)) == NEGATE_EXPR
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|| (TREE_CODE (TREE_OPERAND (t, 0)) == INTEGER_CST
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&& may_negate_without_overflow_p (TREE_OPERAND (t, 0))))
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return true;
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}
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else if (negate_expr_p (TREE_OPERAND (t, 0)))
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return true;
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return negate_expr_p (TREE_OPERAND (t, 1));
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case NOP_EXPR:
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case NOP_EXPR:
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/* Negate -((double)float) as (double)(-float). */
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/* Negate -((double)float) as (double)(-float). */
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@ -682,16 +695,20 @@ fold_negate_expr (location_t loc, tree t)
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return fold_build2_loc (loc, TREE_CODE (t), type,
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return fold_build2_loc (loc, TREE_CODE (t), type,
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TREE_OPERAND (t, 0), negate_expr (tem));
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TREE_OPERAND (t, 0), negate_expr (tem));
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}
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}
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/* If overflow is undefined then we have to be careful because
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we ask whether it's ok to associate the negate with the
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division which is not ok for example for
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-((a - b) / c) where (-(a - b)) / c may invoke undefined
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overflow because of negating INT_MIN. So do not use
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negate_expr_p here but open-code the two important cases. */
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tem = TREE_OPERAND (t, 0);
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tem = TREE_OPERAND (t, 0);
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if (negate_expr_p (tem))
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if ((INTEGRAL_TYPE_P (type)
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{
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&& (TREE_CODE (tem) == NEGATE_EXPR
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if (INTEGRAL_TYPE_P (type)
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|| (TREE_CODE (tem) == INTEGER_CST
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&& (TREE_CODE (tem) != INTEGER_CST
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&& may_negate_without_overflow_p (tem))))
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|| tree_int_cst_equal (tem, TYPE_MIN_VALUE (type))))
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|| !INTEGRAL_TYPE_P (type))
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fold_overflow_warning (warnmsg, WARN_STRICT_OVERFLOW_MISC);
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return fold_build2_loc (loc, TREE_CODE (t), type,
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return fold_build2_loc (loc, TREE_CODE (t), type,
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negate_expr (tem), TREE_OPERAND (t, 1));
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negate_expr (tem), TREE_OPERAND (t, 1));
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}
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}
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}
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break;
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break;
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@ -1,3 +1,8 @@
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2013-09-03 Richard Biener <rguenther@suse.de>
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PR middle-end/57656
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* gcc.dg/torture/pr57656.c: New testcase.
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2013-09-03 Richard Biener <rguenther@suse.de>
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2013-09-03 Richard Biener <rguenther@suse.de>
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PR middle-end/57287
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PR middle-end/57287
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@ -0,0 +1,13 @@
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/* { dg-do run } */
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/* { dg-options "-fstrict-overflow" } */
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int main (void)
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{
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int a = -1;
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int b = __INT_MAX__;
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int c = 2;
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int t = 1 - ((a - b) / c); // t = 1 - ( __INT_MIN__ / 2 )
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if (t != (1 - (-1 - __INT_MAX__) / 2))
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__builtin_abort();
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return 0;
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}
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