71 lines
2.2 KiB
Diff
71 lines
2.2 KiB
Diff
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
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PR middle-end/39867
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* fold-const.c (fold_cond_expr_with_comparison): When folding
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> and >= to MAX, make sure the MAX uses the same type as the
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comparison's operands.
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* gcc.dg/pr39867.c: New.
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--- gcc/fold-const.c (revision 146581)
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+++ gcc/fold-const.c (working copy)
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@@ -5337,31 +5337,34 @@ fold_cond_expr_with_comparison (tree typ
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break;
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case GT_EXPR:
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- /* If C1 is C2 - 1, this is max(A, C2). */
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+ /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
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+ MAX_EXPR, to preserve the signedness of the comparison. */
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if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type),
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OEP_ONLY_CONST)
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&& operand_equal_p (arg01,
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const_binop (MINUS_EXPR, arg2,
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build_int_cst (type, 1), 0),
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OEP_ONLY_CONST))
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- return pedantic_non_lvalue (fold_build2 (MAX_EXPR,
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- type,
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- fold_convert (type, arg1),
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- arg2));
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+ return pedantic_non_lvalue (fold_convert (type,
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+ fold_build2 (MAX_EXPR, TREE_TYPE (arg00),
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+ arg00,
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+ fold_convert (TREE_TYPE (arg00),
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+ arg2))));
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break;
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case GE_EXPR:
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- /* If C1 is C2 + 1, this is max(A, C2). */
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+ /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
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if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type),
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OEP_ONLY_CONST)
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&& operand_equal_p (arg01,
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const_binop (PLUS_EXPR, arg2,
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build_int_cst (type, 1), 0),
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OEP_ONLY_CONST))
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- return pedantic_non_lvalue (fold_build2 (MAX_EXPR,
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- type,
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- fold_convert (type, arg1),
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- arg2));
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+ return pedantic_non_lvalue (fold_convert (type,
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+ fold_build2 (MAX_EXPR, TREE_TYPE (arg00),
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+ arg00,
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+ fold_convert (TREE_TYPE (arg00),
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+ arg2))));
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break;
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case NE_EXPR:
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break;
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--- gcc/testsuite/gcc.dg/pr39867.c 2009-04-21 23:33:56.143009234 +0200
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+++ gcc/testsuite/gcc.dg/pr39867.c 2009-04-24 09:20:07.000000000 +0200
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@@ -0,0 +1,11 @@
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+/* { dg-do link } */
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+/* { dg-options "-O2" } */
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+
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+int main (void)
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+{
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+ int exp = -1;
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+ /* Wrong folding of the LHS to an unsigned MAX leads to 4294967295 > 2. */
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+ if ((exp < 2 ? 2U : (unsigned int) exp) != 2)
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+ link_error ();
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+ return 0;
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+}
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