[Bug middle-end/14730] New: [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[Bug middle-end/14730] New: [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[pinskia at gcc dot gnu dot org]

int t(char i)
{
  switch (i)
  {
    case 1:
    case 7:
    case 10:
    case 14:
    case 9:
    case 256:
      return 0;
  }
  return 0;
}

-- 
           Summary: [tree-ssa] ICE on a switch statement with a case which
                    is bigger than the type of switcher
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |tree-ssa


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[falk at debian dot org]

------- Additional Comments From falk at debian dot org  2004-03-25 09:55 -------
Confirmed. Here's the ICE:

test.c:3: internal compiler error: in tree_low_cst, at tree.c:3452

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[bje at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |bje at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[bje at au1 dot ibm dot com]

------- Additional Comments From bje at au1 dot ibm dot com  2004-04-01 05:02 -------
Subject: PR 14730

I've spent some time looking into this PR.

The problem stems from the fact that the switch's controlling
expression (an expression of type char in the test case) generates a
cast to int early in tree production, but the cast is later optimised
away.  Without the cast, the case label value 256 overflows a char,
becomes a case label value 0 and the case range is miscalculated.
Things quickly go south from there.

T.0_2 = (int)i_1;
switch (T.0_2)
  {
    case 1: goto <L0>;
    case 7: goto <L0>;
    case 10: goto <L0>;
    case 14: goto <L0>;
    case 9: goto <L0>;
    case 256: goto <L0>;
    default : goto <L6>;
  }

After optimisations are applied, the tree looks like this:

switch (i_1)
  {
    case 1: goto <L0>;
    case 7: goto <L0>;
    case 10: goto <L0>;
    case 14: goto <L0>;
    case 9: goto <L0>;
    case 256: goto <L0>;
    default : goto <L6>;
  }

It seems that one of the optimisers is removing the T.0_2 variable and
the cast.  I'll keep digging.

Ben


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[bje at au1 dot ibm dot com]

------- Additional Comments From bje at au1 dot ibm dot com  2004-04-01 07:18 -------
Subject: PR 14730

The bug originator says that he expects that the out-of-range case
label would be optimised away, however I feel that we should focus on
getting tree-ssa to not regress from the mainline at this stage (which
retains the case 256 label and promotes the controlling expression to
int).

The dce2 pass is removing the cast:

  Eliminating unnecessary statements:
  Deleting : T.0_2 = (int)i_1;

Ben


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[bje at au1 dot ibm dot com]

------- Additional Comments From bje at au1 dot ibm dot com  2004-04-02 05:37 -------
Subject: PR 14730

I've tracked down the source of this problem and have fixed it with a
crude patch.  I'm now working on a refined patch.

Ben



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[bje at gcc dot gnu dot org]

------- Additional Comments From bje at gcc dot gnu dot org  2004-04-20 23:51 -------
Fixed by this patch:

2004-04-21  Ben Elliston  <bje@au.ibm.com>

        PR middle-end/14730
        * expr.c (expand_expr_real_1) <SWITCH_EXPR>: Discard out of bounds
        case label values and ranges.  Saturate case range values that
        exceed the minimum or maximum permitted value for the controlling
        expression type to TYPE_MIN_VALUE or TYPE_MAX_VALUE.

[testsuite]
2004-04-21  Ben Elliston  <bje@au.ibm.com>

        PR middle-end/14730
        * gcc.c-torture/compile/pr14730.c: New test.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730

[Bug middle-end/14730] [tree-ssa] ICE on a switch statement with a case which is bigger than the type of switcher

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-04-20 23:47 -------
Subject: Bug 14730

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	tree-ssa-20020619-branch
Changes by:	bje@gcc.gnu.org	2004-04-20 23:47:40

Modified files:
	gcc            : ChangeLog.tree-ssa expr.c 
	gcc/testsuite  : ChangeLog.tree-ssa 
Added files:
	gcc/testsuite/gcc.c-torture/compile: pr14730.c 

Log message:
	2004-04-21  Ben Elliston  <bje@au.ibm.com>
	
	PR middle-end/14730
	* expr.c (expand_expr_real_1) <SWITCH_EXPR>: Discard out of bounds
	case label values and ranges.  Saturate case range values that
	exceed the minimum or maximum permitted value for the controlling
	expression type to TYPE_MIN_VALUE or TYPE_MAX_VALUE.
	
	[testsuite]
	2004-04-21  Ben Elliston  <bje@au.ibm.com>
	
	PR middle-end/14730
	* gcc.c-torture/compile/pr14730.c: New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.tree-ssa.diff?cvsroot=gcc&only_with_tag=tree-ssa-20020619-branch&r1=1.1.2.1341&r2=1.1.2.1342
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/expr.c.diff?cvsroot=gcc&only_with_tag=tree-ssa-20020619-branch&r1=1.467.2.86&r2=1.467.2.87
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.tree-ssa.diff?cvsroot=gcc&only_with_tag=tree-ssa-20020619-branch&r1=1.1.2.224&r2=1.1.2.225
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/compile/pr14730.c.diff?cvsroot=gcc&only_with_tag=tree-ssa-20020619-branch&r1=NONE&r2=1.1.2.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14730