[gcc r14-8895] lower-bitint: Fix up additions of EH edges [PR113818]

[gcc r14-8895] lower-bitint: Fix up additions of EH edges [PR113818]

[Jakub Jelinek]

https://gcc.gnu.org/g:6c124873f5197ca8aac5acfada4b0e7fba49807f

commit r14-8895-g6c124873f5197ca8aac5acfada4b0e7fba49807f
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Feb 9 11:07:34 2024 +0100

    lower-bitint: Fix up additions of EH edges [PR113818]
    
    Due to -fnon-call-exceptions the bitint lowering adds new EH edges
    in various places, so that the EH edge points from handling (e.g. load or
    store) of each of the limbs.  The problem is that the EH edge destination
    as shown in the testcase can have some PHIs.  If it is just a virtual
    PHI, no big deal, the pass uses TODO_update_ssa_only_virtuals, but if
    it has other PHIs, I think we need to copy the values from the preexisting
    corresponding EH edge (which is from the original stmt to the EH pad)
    to the newly added EH edge, so that the PHI arguments are the same rather
    than missing (which ICEs during checking at the end of the pass).
    
    This patch adds a function to do that and uses it whenever adding EH edges.
    
    2024-02-09  Jakub Jelinek  <jakub@redhat.com>
    
            PR tree-optimization/113818
            * gimple-lower-bitint.cc (add_eh_edge): New function.
            (bitint_large_huge::handle_load,
            bitint_large_huge::lower_mergeable_stmt,
            bitint_large_huge::lower_muldiv_stmt): Use it.
    
            * gcc.dg/bitint-89.c: New test.

Diff:
---
 gcc/gimple-lower-bitint.cc       | 47 ++++++++++++++++++++++++++--------------
 gcc/testsuite/gcc.dg/bitint-89.c | 22 +++++++++++++++++++
 2 files changed, 53 insertions(+), 16 deletions(-)

diff --git a/gcc/gimple-lower-bitint.cc b/gcc/gimple-lower-bitint.cc
index 42027312bd77..8dcce6601478 100644
--- a/gcc/gimple-lower-bitint.cc
+++ b/gcc/gimple-lower-bitint.cc
@@ -1681,6 +1681,27 @@ bitint_large_huge::handle_cast (tree lhs_type, tree rhs1, tree idx)
   return NULL_TREE;
 }
 
+/* Add a new EH edge from SRC to EH_EDGE->dest, where EH_EDGE
+   is an older EH edge, and except for virtual PHIs duplicate the
+   PHI argument from the EH_EDGE to the new EH edge.  */
+
+static void
+add_eh_edge (basic_block src, edge eh_edge)
+{
+  edge e = make_edge (src, eh_edge->dest, EDGE_EH);
+  e->probability = profile_probability::very_unlikely ();
+  for (gphi_iterator gsi = gsi_start_phis (eh_edge->dest);
+       !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gphi *phi = gsi.phi ();
+      tree lhs = gimple_phi_result (phi);
+      if (virtual_operand_p (lhs))
+	continue;
+      const phi_arg_d *arg = gimple_phi_arg (phi, eh_edge->dest_idx);
+      add_phi_arg (phi, arg->def, e, arg->locus);
+    }
+}
+
 /* Helper function for handle_stmt method, handle a load from memory.  */
 
 tree
@@ -1756,8 +1777,7 @@ bitint_large_huge::handle_load (gimple *stmt, tree idx)
 		  if (eh_edge)
 		    {
 		      edge e = split_block (gsi_bb (m_gsi), g);
-		      make_edge (e->src, eh_edge->dest, EDGE_EH)->probability
-			= profile_probability::very_unlikely ();
+		      add_eh_edge (e->src, eh_edge);
 		      m_gsi = gsi_after_labels (e->dest);
 		      if (gsi_bb (save_gsi) == e->src)
 			{
@@ -1876,8 +1896,7 @@ bitint_large_huge::handle_load (gimple *stmt, tree idx)
 		{
 		  edge e = split_block (gsi_bb (m_gsi), g);
 		  m_gsi = gsi_after_labels (e->dest);
-		  make_edge (e->src, eh_edge->dest, EDGE_EH)->probability
-		    = profile_probability::very_unlikely ();
+		  add_eh_edge (e->src, eh_edge);
 		}
 	    }
 	  if (conditional)
@@ -1934,8 +1953,7 @@ normal_load:
 	{
 	  edge e = split_block (gsi_bb (m_gsi), g);
 	  m_gsi = gsi_after_labels (e->dest);
-	  make_edge (e->src, eh_edge->dest, EDGE_EH)->probability
-	    = profile_probability::very_unlikely ();
+	  add_eh_edge (e->src, eh_edge);
 	}
       if (tree_fits_uhwi_p (idx))
 	{
@@ -2554,8 +2572,8 @@ bitint_large_huge::lower_mergeable_stmt (gimple *stmt, tree_code &cmp_code,
 			{
 			  edge e = split_block (gsi_bb (m_gsi), g);
 			  m_gsi = gsi_after_labels (e->dest);
-			  make_edge (e->src, eh_pad, EDGE_EH)->probability
-			    = profile_probability::very_unlikely ();
+			  add_eh_edge (e->src,
+				       find_edge (gimple_bb (stmt), eh_pad));
 			}
 		    }
 		  if (kind == bitint_prec_large)
@@ -2633,8 +2651,8 @@ bitint_large_huge::lower_mergeable_stmt (gimple *stmt, tree_code &cmp_code,
 		    {
 		      edge e = split_block (gsi_bb (m_gsi), g);
 		      m_gsi = gsi_after_labels (e->dest);
-		      make_edge (e->src, eh_pad, EDGE_EH)->probability
-			= profile_probability::very_unlikely ();
+		      add_eh_edge (e->src,
+				   find_edge (gimple_bb (stmt), eh_pad));
 		    }
 		}
 	      if (new_bb)
@@ -2777,8 +2795,7 @@ bitint_large_huge::lower_mergeable_stmt (gimple *stmt, tree_code &cmp_code,
 		{
 		  edge e = split_block (gsi_bb (m_gsi), g);
 		  m_gsi = gsi_after_labels (e->dest);
-		  make_edge (e->src, eh_pad, EDGE_EH)->probability
-		    = profile_probability::very_unlikely ();
+		  add_eh_edge (e->src, find_edge (gimple_bb (stmt), eh_pad));
 		}
 	    }
 	  if (kind == bitint_prec_huge && i == (bo_bit != 0))
@@ -2822,8 +2839,7 @@ bitint_large_huge::lower_mergeable_stmt (gimple *stmt, tree_code &cmp_code,
 	    {
 	      edge e = split_block (gsi_bb (m_gsi), g);
 	      m_gsi = gsi_after_labels (e->dest);
-	      make_edge (e->src, eh_pad, EDGE_EH)->probability
-		= profile_probability::very_unlikely ();
+	      add_eh_edge (e->src, find_edge (gimple_bb (stmt), eh_pad));
 	    }
 	}
     }
@@ -3479,8 +3495,7 @@ bitint_large_huge::lower_muldiv_stmt (tree obj, gimple *stmt)
 	{
 	  edge e2 = split_block (gsi_bb (m_gsi), g);
 	  m_gsi = gsi_after_labels (e2->dest);
-	  make_edge (e2->src, e1->dest, EDGE_EH)->probability
-	    = profile_probability::very_unlikely ();
+	  add_eh_edge (e2->src, e1);
 	}
     }
 }
diff --git a/gcc/testsuite/gcc.dg/bitint-89.c b/gcc/testsuite/gcc.dg/bitint-89.c
new file mode 100644
index 000000000000..d4468dfd8743
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitint-89.c
@@ -0,0 +1,22 @@
+/* PR tree-optimization/113818 */
+/* { dg-do compile { target bitint } } */
+/* { dg-options "-Os -fnon-call-exceptions -finstrument-functions-once" } */
+
+int c, i;
+void bar (int *);
+
+#if __BITINT_MAXWIDTH__ >= 129
+_BitInt(129) *a;
+#else
+_BitInt(63) *a;
+#endif
+
+void
+foo (void)
+{
+  if (c)
+    return;
+  int q;
+  a[i] = 0;
+  bar (&q);
+}