[PATCH] tree-optimization/106226 - move vectorizer virtual SSA update

[PATCH] tree-optimization/106226 - move vectorizer virtual SSA update

[Richard Biener]

When we knowingly have broken virtual SSA form we need to update
it before we eventually perform slpeel manual updating which will
call delete_update_ssa.  Currently that's done on-demand but
communicating whether it's a known unavoidable case is broken
there.  The following makes that a synchronous operation but
instead of actually performing the update we instead recod the
need, clear the update SSA sub-state and force virtual renaming
at the very end of the vectorization pass.

This reorg exposes an issue like with LOAD_LANES in simd-clone
handling which I patch up in a similar fashion.  So it might
uncover new latent issues elsewhere.

Bootstrap / regtest re-running on x86_64-unknown-linux-gnu
after fixing the simdclode issue.

Richard.

	PR tree-optimization/106226
	* tree-vect-loop-manip.cc (vect_do_peeling): Assert that
	no SSA update is needed.  Move virtual SSA update ...
	* tree-vectorizer.cc (pass_vectorize::execute): ... here,
	via forced virtual renaming when TODO_update_ssa_only_virtuals
	is queued.
	(vect_transform_loops): Return TODO_update_ssa_only_virtuals
	when virtual SSA update is required.
	(try_vectorize_loop_1): Adjust.
	* tree-vect-stmts.c (vectorizable_simd_clone_call): Allow
	virtual renaming if the ABI forces an aggregate return
	but the original call did not have a virtual definition.

	* gfortran.dg/pr106226.f: New testcase.
---
 gcc/testsuite/gfortran.dg/pr106226.f | 37 ++++++++++++++++++++++++++++
 gcc/tree-vect-loop-manip.cc          | 11 ++++-----
 gcc/tree-vect-stmts.cc               |  8 ++++++
 gcc/tree-vectorizer.cc               | 29 +++++++++++++++++++---
 4 files changed, 76 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr106226.f

diff --git a/gcc/testsuite/gfortran.dg/pr106226.f b/gcc/testsuite/gfortran.dg/pr106226.f
new file mode 100644
index 00000000000..19237bc5a71
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr106226.f
@@ -0,0 +1,37 @@
+! { dg-do compile }
+! { dg-options "-O3 -std=legacy" }
+
+      SUBROUTINE EFTORD(DM,CHDINT,L4)
+      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
+      PARAMETER (MXPT=100, MXFRG=50, MXFGPT=MXPT*MXFRG)
+      DIMENSION DM(*),CHDINT(L4)
+      COMMON /FGRAD / DEF0,DEFT0,TORQ0
+     *                ,ATORQ(3,MXFRG)
+      COMMON /CSSTV / CX,CY,CZ
+     *                EFBTRM(MXFGPT),EFATRM2(MXFGPT),EFBTRM2(MXFGPT),
+     *                EFDIP(3,MXFGPT),EFQAD(6,MXFGPT),
+     *                EFOCT(10,MXFGPT),FRGNME(MXFGPT)
+      IF(NROOTS.EQ.5) CALL ROOT5
+      IF(NROOTS.EQ.6) CALL ROOT6
+      IF(NROOTS.GE.7) THEN
+         CALL ABRT
+      END IF
+      DO 403 I = 1,IJ
+      CHDINT(ICC)=CHDINT(ICC)-DUM*DUMY
+      ICC=ICC+1
+ 403  CONTINUE
+      CHDINT(ICC)=CHDINT(ICC)-DUM*DUMY
+      DO 550 J=MINJ,MAX
+      LJ=LOCJ+J
+      IF (LI-LJ) 920,940,940
+  920 ID = LJ
+      GO TO 960
+  940 ID = LI
+  960 NN = (ID*(ID-1))/2+JD
+      DUM = DM(NN)
+      ATORQ(1,INF)=ATORQ(1,INF)-DUM*(CHDINT(ICC+1)*EFDIP(3,IC)
+     $           -CHDINT(ICC+2)*EFDIP(2,IC))
+      ICC=ICC+1
+      ICC=ICC+1
+  550 CONTINUE
+      END
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index d7410d7b4bd..2c2b4f7bd53 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -2696,12 +2696,11 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
   class loop *first_loop = loop;
   bool irred_flag = loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP;
 
-  /* We should not have to update virtual SSA form here but some
-     transforms involve creating new virtual definitions which makes
-     updating difficult.  */
-  gcc_assert (!need_ssa_update_p (cfun)
-	      || loop_vinfo->any_known_not_updated_vssa);
-  update_ssa (TODO_update_ssa_only_virtuals);
+  /* SSA form needs to be up-to-date since we are going to manually
+     update SSA form in slpeel_tree_duplicate_loop_to_edge_cfg and delete all
+     update SSA state after that, so we have to make sure to not lose any
+     pending update needs.  */
+  gcc_assert (!need_ssa_update_p (cfun));
 
   create_lcssa_for_virtual_phi (loop);
 
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 3db6620dd42..01d982eea98 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -4247,6 +4247,14 @@ vectorizable_simd_clone_call (vec_info *vinfo, stmt_vec_info stmt_info,
 
   if (!vec_stmt) /* transformation not required.  */
     {
+      /* When the original call is pure or const but the SIMD ABI dictates
+	 an aggregate return we will have to use a virtual definition and
+	 in a loop eventually even need to add a virtual PHI.  That's
+	 not straight-forward so allow to fix this up via renaming.  */
+      if (gimple_call_lhs (stmt)
+	  && !gimple_vdef (stmt)
+	  && TREE_CODE (TREE_TYPE (TREE_TYPE (bestn->decl))) == ARRAY_TYPE)
+	vinfo->any_known_not_updated_vssa = true;
       STMT_VINFO_SIMD_CLONE_INFO (stmt_info).safe_push (bestn->decl);
       for (i = 0; i < nargs; i++)
 	if ((bestn->simdclone->args[i].arg_type
diff --git a/gcc/tree-vectorizer.cc b/gcc/tree-vectorizer.cc
index 53dc4520963..6ec49511d74 100644
--- a/gcc/tree-vectorizer.cc
+++ b/gcc/tree-vectorizer.cc
@@ -82,6 +82,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "opt-problem.h"
 #include "internal-fn.h"
 #include "tree-ssa-sccvn.h"
+#include "tree-into-ssa.h"
 
 /* Loop or bb location, with hotness information.  */
 dump_user_location_t vect_location;
@@ -982,7 +983,7 @@ set_uid_loop_bbs (loop_vec_info loop_vinfo, gimple *loop_vectorized_call,
 
 /* Generate vectorized code for LOOP and its epilogues.  */
 
-static void
+static unsigned
 vect_transform_loops (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
 		      loop_p loop, gimple *loop_vectorized_call,
 		      function *fun)
@@ -1020,9 +1021,25 @@ vect_transform_loops (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
 	  = simduid_to_vf_data;
     }
 
+  /* We should not have to update virtual SSA form here but some
+     transforms involve creating new virtual definitions which makes
+     updating difficult.
+     We delay the actual update to the end of the pass but avoid
+     confusing ourselves by forcing need_ssa_update_p () to false.  */
+  unsigned todo = 0;
+  if (need_ssa_update_p (cfun))
+    {
+      gcc_assert (loop_vinfo->any_known_not_updated_vssa);
+      fun->gimple_df->ssa_renaming_needed = false;
+      todo |= TODO_update_ssa_only_virtuals;
+    }
+  gcc_assert (!need_ssa_update_p (cfun));
+
   /* Epilogue of vectorized loop must be vectorized too.  */
   if (new_loop)
-    vect_transform_loops (simduid_to_vf_htab, new_loop, NULL, fun);
+    todo |= vect_transform_loops (simduid_to_vf_htab, new_loop, NULL, fun);
+
+  return todo;
 }
 
 /* Try to vectorize LOOP.  */
@@ -1133,7 +1150,8 @@ try_vectorize_loop_1 (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
 
   (*num_vectorized_loops)++;
   /* Transform LOOP and its epilogues.  */
-  vect_transform_loops (simduid_to_vf_htab, loop, loop_vectorized_call, fun);
+  ret |= vect_transform_loops (simduid_to_vf_htab, loop,
+			       loop_vectorized_call, fun);
 
   if (loop_vectorized_call)
     {
@@ -1332,6 +1350,11 @@ pass_vectorize::execute (function *fun)
 
   if (num_vectorized_loops > 0)
     {
+      /* We are collecting some corner cases where we need to update
+	 virtual SSA form via the TODO but delete the queued update-SSA
+	 state.  Force renaming if we think that might be necessary.  */
+      if (ret & TODO_update_ssa_only_virtuals)
+	mark_virtual_operands_for_renaming (cfun);
       /* If we vectorized any loop only virtual SSA form needs to be updated.
 	 ???  Also while we try hard to update loop-closed SSA form we fail
 	 to properly do this in some corner-cases (see PR56286).  */
-- 
2.36.1