[PATH]: PR middlend/38385 fix
Thu Jan 8 12:02:00 GMT 2009
as Richard recommended this patch fixes pr38385 by propagation and
removing of phis from loop exit block.
Tested and bootstraped on x86_64-unknown-linux-gnu.
Ok for mainline ?
> >>> This pr is caused because after removing bbs in generate_builtin
> >>> (tree-loop-distribution.c) some phis has bad incoming edges. This
> >>> patch tryes to fix it.
> >>> Tested and bootstraped on x86_64-unknown-linux-gnu.
> >>> Ok for mainline ?
> >> Looks good to me, but I cannot approve it.
> > I don't follow. You create an edge from the preheader to the loop exit
> > and now use the values from the exit edge for that edge? If we
> > are in loop-closed SSA form we should not need to care at all here.
> > It is more likely that we need to split some block before removing the
> > loop.
> Err, wait. These _are_ the loop-closed PHI nodes. You should be able
> to just remove them by propagation.
* tree-loop-distribution.c (prop_phis): New function.
(generate_builtin): Call prop_phis.
* testsuite/gcc.dg/tree-ssa/pr38385.c: New file.
--- tree-loop-distribution.c (revision 143184)
+++ tree-loop-distribution.c (working copy)
@@ -331,6 +331,37 @@ generate_memset_zero (gimple stmt, tree
+/* Propagate phis in bb b to their uses and remove them. */
+prop_phis (basic_block b)
+ gimple_stmt_iterator psi;
+ gimple_seq phis = phi_nodes (b);
+ for (psi = gsi_start (phis); !gsi_end_p (psi); )
+ gimple phi = gsi_stmt (psi);
+ tree def = gimple_phi_result (phi), use = gimple_phi_arg_def (phi, 0);
+ if (!is_gimple_reg (def))
+ imm_use_iterator iter;
+ use_operand_p use_p;
+ gimple stmt;
+ FOR_EACH_IMM_USE_STMT (stmt, iter, def)
+ FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+ SET_USE (use_p, use);
+ replace_uses_by (def, use);
+ remove_phi_node (&psi, true);
/* Tries to generate a builtin function for the instructions of LOOP
pointed to by the bits set in PARTITION. Returns true when the
operation succeeded. */
@@ -400,12 +431,15 @@ generate_builtin (struct loop *loop, bit
unsigned nbbs = loop->num_nodes;
basic_block src = loop_preheader_edge (loop)->src;
basic_block dest = single_exit (loop)->dest;
+ prop_phis (dest);
make_edge (src, dest, EDGE_FALLTHRU);
set_immediate_dominator (CDI_DOMINATORS, dest, src);
for (i = 0; i < nbbs; i++)
+ merge_blocks (src, dest);
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