diff mbox

Fix remove_unreachable_handlers (PR tree-optimization/48794, tree-optimization/48611)

Message ID 20110509191915.GY17079@tyan-ft48-01.lab.bos.redhat.com
State New
Headers show

Commit Message

Jakub Jelinek May 9, 2011, 7:19 p.m. UTC 
Hi!

As the new testcase shows, while my PR48611 patch stopped the problem from
triggering on that testcase, it wasn't a real fix, just (IMHO) right thing
to do to get better code.

The real problem seems to be that if for whatever reason some optimizations
don't happen or don't happen fully (in the testcase because of a series
of -fno-* options), we might end up with an EH region where nothing inside
of the region might throw, but there are RESX or EH_DISPATCH stmts
referencing that region.  If the region is removed as unreachable, but the
RESX or EH_DISPATCH stays, it references a removed region and it will ICE
during inlining or afterwards.

The following patch fixes it by just keeping such regions around, I think it
shouldn't happen if people don't turn optimizations off or at least
shouldn't happen often.  Other alternative would be to modify
RESX/EH_HANDLER referencing the unreachable regions, the question is
what to put there instead or if it can be e.g. removed altogether or
replaced with __builtin_trap.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/4.6?

2011-05-09  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/48611
	PR tree-optimization/48794
	* tree-eh.c (remove_unreachable_handlers): Don't remove regions
	referenced from RESX or EH_DISPATCH arguments.

	* gfortran.dg/gomp/pr48611.f90: New test.
	* gfortran.dg/gomp/pr48794.f90: New test.


	Jakub
diff mbox

Patch

--- gcc/tree-eh.c.jj	2011-05-02 18:39:28.000000000 +0200
+++ gcc/tree-eh.c	2011-05-09 17:31:12.000000000 +0200
@@ -3317,6 +3317,19 @@  remove_unreachable_handlers (void)
 	      SET_BIT (r_reachable, region->index);
 	      SET_BIT (lp_reachable, lp_nr);
 	    }
+
+	  /* Avoid removing regions referenced from RESX/EH_DISPATCH.  */
+	  switch (gimple_code (stmt))
+	    {
+	    case GIMPLE_RESX:
+	      SET_BIT (r_reachable, gimple_resx_region (stmt));
+	      break;
+	    case GIMPLE_EH_DISPATCH:
+	      SET_BIT (r_reachable, gimple_eh_dispatch_region (stmt));
+	      break;
+	    default:
+	      break;
+	    }
 	}
     }
 
--- gcc/testsuite/gfortran.dg/gomp/pr48611.f90.jj	2011-05-09 17:33:15.000000000 +0200
+++ gcc/testsuite/gfortran.dg/gomp/pr48611.f90	2011-05-09 17:32:10.000000000 +0200
@@ -0,0 +1,12 @@ 
+! PR tree-optimization/48611
+! { dg-do compile }
+! { dg-options "-Os -fopenmp -fexceptions -fno-tree-ccp -fno-tree-copy-prop" }
+
+  integer, allocatable :: a(:)
+  logical :: l
+!$omp parallel private (a) reduction (.or.:l)
+  do i = 1, 7
+    a(:) = i
+  end do
+!$omp end parallel
+end
--- gcc/testsuite/gfortran.dg/gomp/pr48794.f90.jj	2011-05-09 17:33:19.000000000 +0200
+++ gcc/testsuite/gfortran.dg/gomp/pr48794.f90	2011-05-09 17:33:35.000000000 +0200
@@ -0,0 +1,12 @@ 
+! PR tree-optimization/48794
+! { dg-do compile }
+! { dg-options "-Os -fopenmp -fexceptions -fno-tree-ccp -fno-tree-copy-prop" }
+
+  integer, allocatable :: a(:)
+  logical :: l
+  if (allocated (a)) call abort
+!$omp parallel private (a) reduction (.or.:l)
+  do i = 1, 7
+  end do
+!$omp end parallel
+end