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re PR middle-end/39867 (Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp)

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2009-04-24  Paolo Bonzini  <bonzini@gnu.org>

	PR middle-end/39867
	* fold-const.c (fold_cond_expr_with_comparison): When folding
	> and >= to MAX, make sure the MAX uses the same type as the
	comparison operands.

testsuite:
2009-04-24  Paolo Bonzini  <bonzini@gnu.org>

	PR middle-end/39867
	* gcc.dg/pr39867.c: New.

From-SVN: r146695
This commit is contained in:
Paolo Bonzini 2009-04-24 10:29:18 +00:00 committed by Paolo Bonzini
parent 8d8256c197
commit 30349c7400
4 changed files with 37 additions and 10 deletions
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7
gcc/ChangeLog
View File

@ -1,3 +1,10 @@
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* fold-const.c (fold_cond_expr_with_comparison): When folding
> and >= to MAX, make sure the MAX uses the same type as the
comparison's operands.
2009-04-24 Nick Clifton <nickc@redhat.com>
* config/frv/frv.c (frv_frame_access): Do not use reg+reg

23
gcc/fold-const.c
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@ -5337,31 +5337,34 @@ fold_cond_expr_with_comparison (tree type, tree arg0, tree arg1, tree arg2)
break;
case GT_EXPR:
/* If C1 is C2 - 1, this is max(A, C2). */
/* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
MAX_EXPR, to preserve the signedness of the comparison. */
if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type),
OEP_ONLY_CONST)
&& operand_equal_p (arg01,
const_binop (MINUS_EXPR, arg2,
build_int_cst (type, 1), 0),
OEP_ONLY_CONST))
return pedantic_non_lvalue (fold_build2 (MAX_EXPR,
type,
fold_convert (type, arg1),
arg2));
return pedantic_non_lvalue (fold_convert (type,
fold_build2 (MAX_EXPR, TREE_TYPE (arg00),
arg00,
fold_convert (TREE_TYPE (arg00),
arg2))));
break;
case GE_EXPR:
/* If C1 is C2 + 1, this is max(A, C2). */
/* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type),
OEP_ONLY_CONST)
&& operand_equal_p (arg01,
const_binop (PLUS_EXPR, arg2,
build_int_cst (type, 1), 0),
OEP_ONLY_CONST))
return pedantic_non_lvalue (fold_build2 (MAX_EXPR,
type,
fold_convert (type, arg1),
arg2));
return pedantic_non_lvalue (fold_convert (type,
fold_build2 (MAX_EXPR, TREE_TYPE (arg00),
arg00,
fold_convert (TREE_TYPE (arg00),
arg2))));
break;
case NE_EXPR:
break;

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* gcc.dg/pr39867.c: New.
2009-04-24 Janus Weil <janus@gcc.gnu.org>
PR fortran/39861

12
gcc/testsuite/gcc.dg/pr39867.c Normal file
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@ -0,0 +1,12 @@
/* { dg-do link } */
/* { dg-options "-O2" } */
int main (void)
{
int exp = -1;
/* Wrong folding of the LHS to an unsigned MAX leads to 4294967295 != 2. */
if ((exp < 2 ? 2U : (unsigned int) exp) != 2)
link_error ();
return 0;
}