| Message ID | 20110526103241.GU17079@tyan-ft48-01.lab.bos.redhat.com |
|---|---|
| State | New |
| Headers | show |
On 05/26/2011 06:32 AM, Jakub Jelinek wrote: > gimplify_cond_expr knows how to gimplify this, but shortcut_cond_r > tried to optimize > if (a ? b : throw 1) goto yes; else goto no; > into > if (a) > if (b) goto yes; else goto no; > else > if (throw 1) goto yes; else goto no; > which ICEs or errors out. Fixed by not trying to optimize > such COND_EXPRs. Why not optimize them to if (!a) throw 1; if (b) goto yes; else goto no; ? Jason
On Thu, May 26, 2011 at 09:26:58AM -0400, Jason Merrill wrote: > On 05/26/2011 06:32 AM, Jakub Jelinek wrote: > >gimplify_cond_expr knows how to gimplify this, but shortcut_cond_r > >tried to optimize > >if (a ? b : throw 1) goto yes; else goto no; > >into > >if (a) > > if (b) goto yes; else goto no; > >else > > if (throw 1) goto yes; else goto no; > >which ICEs or errors out. Fixed by not trying to optimize > >such COND_EXPRs. > > Why not optimize them to > > if (!a) > throw 1; > if (b) goto yes; else goto no; > > ? That is how it ends up being optimized later on, I just think given how long the bug has been in this is so rare that we don't need to try to optimize it already at the gimplifier level. Jakub
On 05/26/2011 09:41 AM, Jakub Jelinek wrote: > That is how it ends up being optimized later on, I just think > given how long the bug has been in this is so rare that > we don't need to try to optimize it already at the gimplifier level. Makes sense. Jason
--- gcc/gimplify.c.jj 2011-05-20 08:14:08.000000000 +0200 +++ gcc/gimplify.c 2011-05-26 09:12:54.000000000 +0200 @@ -2573,7 +2573,9 @@ shortcut_cond_r (tree pred, tree *true_l new_locus); append_to_statement_list (t, &expr); } - else if (TREE_CODE (pred) == COND_EXPR) + else if (TREE_CODE (pred) == COND_EXPR + && !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 1))) + && !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 2)))) { location_t new_locus; @@ -2581,7 +2583,10 @@ shortcut_cond_r (tree pred, tree *true_l if (a) if (b) goto yes; else goto no; else - if (c) goto yes; else goto no; */ + if (c) goto yes; else goto no; + + Don't do this if one of the arms has void type, which can happen + in C++ when the arm is throw. */ /* Keep the original source location on the first 'if'. Set the source location of the ? on the second 'if'. */ --- gcc/testsuite/g++.dg/eh/cond5.C.jj 2011-05-26 09:15:24.000000000 +0200 +++ gcc/testsuite/g++.dg/eh/cond5.C 2011-05-26 09:07:16.000000000 +0200 @@ -0,0 +1,43 @@ +// PR c++/49165 +// { dg-do run } + +extern "C" void abort (); + +int +foo (bool x, int y) +{ + if (y < 10 && (x ? true : throw 1)) + y++; + if (y > 20 || (x ? true : throw 2)) + y++; + return y; +} + +int +main () +{ + if (foo (true, 0) != 2 + || foo (true, 10) != 11 + || foo (false, 30) != 31) + abort (); + try + { + foo (false, 0); + abort (); + } + catch (int i) + { + if (i != 1) + abort (); + } + try + { + foo (false, 10); + abort (); + } + catch (int i) + { + if (i != 2) + abort (); + } +}