[PATCH] tree-optimization/106249 - unroll-and-jam and LC SSA upate

Richard Biener rguenther@suse.de
Wed Jul 13 07:35:43 GMT 2022


When I delayed the LC SSA update in unroll-and-jam this exposed
an issue that tree_transform_and_unroll_loop does a full function
LC SSA verification when new_loop is NULL (when it doesn't need to
do versioning).  That wasn't intended.  I also took the chance
to make the versioning in tree_transform_and_unroll_loop use
TODO_update_ssa_nophi for the loop versioning SSA update which
I somehow missed earlier.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR tree-optimization/106249
	* tree-ssa-loop-manip.cc (tree_transform_and_unroll_loop):
	Only verify LC SSA of the new_loop if we created it.
	Use TODO_update_ssa_nophi for the SSA update after versioning
	the loop.

	* gcc.dg/pr106249.c: New testcase.
---
 gcc/testsuite/gcc.dg/pr106249.c | 16 ++++++++++++++++
 gcc/tree-ssa-loop-manip.cc      |  5 +++--
 2 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr106249.c

diff --git a/gcc/testsuite/gcc.dg/pr106249.c b/gcc/testsuite/gcc.dg/pr106249.c
new file mode 100644
index 00000000000..f97b07fb4da
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106249.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O -floop-unroll-and-jam --param unroll-jam-min-percent=0" } */
+
+void
+foo (double *arr)
+{
+  int i, j;
+
+  for (i = 0; i < 4; ++i)
+    for (j = 0; j < 4; ++j)
+      arr[j] = 0;
+
+  for (i = 1; i < 4; ++i)
+    for (j = 0; j < 4; ++j)
+      arr[j] = 1.0 / (i + 1);
+}
diff --git a/gcc/tree-ssa-loop-manip.cc b/gcc/tree-ssa-loop-manip.cc
index c531f1f12fd..410a8516370 100644
--- a/gcc/tree-ssa-loop-manip.cc
+++ b/gcc/tree-ssa-loop-manip.cc
@@ -1208,7 +1208,7 @@ tree_transform_and_unroll_loop (class loop *loop, unsigned factor,
 			       profile_probability::guessed_always (),
 			       true);
       gcc_assert (new_loop != NULL);
-      update_ssa (TODO_update_ssa);
+      update_ssa (TODO_update_ssa_no_phi);
 
       /* Prepare the cfg and update the phi nodes.  Move the loop exit to the
 	 loop latch (and make its condition dummy, for the moment).  */
@@ -1428,7 +1428,8 @@ tree_transform_and_unroll_loop (class loop *loop, unsigned factor,
   checking_verify_flow_info ();
   checking_verify_loop_structure ();
   checking_verify_loop_closed_ssa (true, loop);
-  checking_verify_loop_closed_ssa (true, new_loop);
+  if (new_loop)
+    checking_verify_loop_closed_ssa (true, new_loop);
 }
 
 /* Wrapper over tree_transform_and_unroll_loop for case we do not
-- 
2.35.3


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