Replace VRP threader with a hybrid forward threader.

This patch implements the new hybrid forward threader and replaces the
embedded VRP threader with it.

With all the pieces that have gone in, the implementation of the hybrid
threader is straightforward: convert the current state into
SSA imports that the solver will understand, and let the path solver
precompute ranges and relations for the path.  After this setup is done,
we can use the range_query API to solve gimple statements in the threader.
The forward threader is now engine agnostic so there are no changes to
the threader per se.

I have put the hybrid bits in tree-ssa-threadedge.*, instead of VRP,
because they will also be used in the evrp removal of the DOM/threader,
which is my next task.

Most of the patch, is actually test changes.  I have gone through every
single one and verified that we're correct.  Most were trivial dump
file name changes, but others required going through the IL an
certifying that the different IL was expected.

For example, in pr59597.c, we have one less thread because the
ASSERT_EXPR was getting in the way, and making it seem like things were
not crossing loops.  The hybrid threader sees the correct representation
of the IL, and avoids threading this one case.

The final numbers are a 12.16% improvement in jump threads immediately
after VRP, and a 0.82% improvement in overall jump threads.  The
performance drop is 0.6% (plus the 1.43% hit from moving the embedded
threader into its own pass).  As I've said, I'd prefer to keep the
threader in its own pass, but if this is an issue, we can address this
with a shared ranger when VRP is replaced with an evrp instance
(upcoming).

Note, that these numbers are slightly different than what I originally
posted.  A few correctness tweaks, plus restricting loop threads, made
the difference.  That being said, I was aiming for par.  A 12% gain is
just gravy ;-).  When we merge the threaders, we should see even better
numbers-- and we'll have the benefit of an entire release stress testing
the solver.

As I mentioned in my introductory note, paths ending in MEM_REF
conditional are missing.  In reality, this didn't make a difference, as
it was so rare.  However, as a follow-up, I will distill a test and add
a suitable PR to keep us honest.

There is a one-line change to libgomp/team.c silencing a new used
uninitialized warning.  As my previous work with the threaders has
shown, warnings flare up after each improvement to jump threading.  I
expect this to be no different.  I've promised Jakub to investigate
fully, so I will analyze and add the appropriate PR for the warning
experts.

Oh yeah, the new pass dump is called vrp-threader[12] to match each
VRP[12] pass.  However, there's no reason for it to either be named
vrp-threader, or for it to live in tree-vrp.c.

Tested on x86-64 Linux.

OK?

p.s. "Did I say 5 weeks?  My bad, I meant 5 months."

gcc/ChangeLog:

	* passes.def (pass_vrp_threader): New.
	* tree-pass.h (make_pass_vrp_threader): Add make_pass_vrp_threader.
	* tree-ssa-threadedge.c (hybrid_jt_state::register_equivs_stmt): New.
	(hybrid_jt_simplifier::hybrid_jt_simplifier): New.
	(hybrid_jt_simplifier::simplify): New.
	(hybrid_jt_simplifier::compute_ranges_from_state): New.
	* tree-ssa-threadedge.h (class hybrid_jt_state): New.
	(class hybrid_jt_simplifier): New.
	* tree-vrp.c (execute_vrp): Remove ASSERT_EXPR based jump
	threader.
	(class hybrid_threader): New.
	(hybrid_threader::hybrid_threader): New.
	(hybrid_threader::~hybrid_threader): New.
	(hybrid_threader::before_dom_children): New.
	(hybrid_threader::after_dom_children): New.
	(execute_vrp_threader): New.
	(class pass_vrp_threader): New.
	(make_pass_vrp_threader): New.

libgomp/ChangeLog:

	* team.c: Initialize start_data.
	* testsuite/libgomp.graphite/force-parallel-4.c: Adjust.
	* testsuite/libgomp.graphite/force-parallel-8.c: Adjust.

gcc/testsuite/ChangeLog:

	* gcc.dg/torture/pr55107.c: Adjust.
	* gcc.dg/tree-ssa/phi_on_compare-1.c: Adjust.
	* gcc.dg/tree-ssa/phi_on_compare-2.c: Adjust.
	* gcc.dg/tree-ssa/phi_on_compare-3.c: Adjust.
	* gcc.dg/tree-ssa/phi_on_compare-4.c: Adjust.
	* gcc.dg/tree-ssa/pr21559.c: Adjust.
	* gcc.dg/tree-ssa/pr59597.c: Adjust.
	* gcc.dg/tree-ssa/pr61839_1.c: Adjust.
	* gcc.dg/tree-ssa/pr61839_3.c: Adjust.
	* gcc.dg/tree-ssa/pr71437.c: Adjust.
	* gcc.dg/tree-ssa/ssa-dom-thread-11.c: Adjust.
	* gcc.dg/tree-ssa/ssa-dom-thread-16.c: Adjust.
	* gcc.dg/tree-ssa/ssa-dom-thread-18.c: Adjust.
	* gcc.dg/tree-ssa/ssa-dom-thread-2a.c: Adjust.
	* gcc.dg/tree-ssa/ssa-dom-thread-4.c: Adjust.
	* gcc.dg/tree-ssa/ssa-thread-14.c: Adjust.
	* gcc.dg/tree-ssa/ssa-vrp-thread-1.c: Adjust.
	* gcc.dg/tree-ssa/vrp106.c: Adjust.
	* gcc.dg/tree-ssa/vrp55.c: Adjust.

gcc/passes.def

@@ -212,6 +212,7 @@ along with GCC; see the file COPYING3.  If not see
       NEXT_PASS (pass_merge_phi);
       NEXT_PASS (pass_thread_jumps);
       NEXT_PASS (pass_vrp, true /* warn_array_bounds_p */);
+      NEXT_PASS (pass_vrp_threader);
       NEXT_PASS (pass_dse);
       NEXT_PASS (pass_dce);
       /* pass_stdarg is always run and at this point we execute
@@ -337,6 +338,7 @@ along with GCC; see the file COPYING3.  If not see
       NEXT_PASS (pass_strlen);
       NEXT_PASS (pass_thread_jumps);
       NEXT_PASS (pass_vrp, false /* warn_array_bounds_p */);
+      NEXT_PASS (pass_vrp_threader);
       /* Threading can leave many const/copy propagations in the IL.
 	 Clean them up.  Instead of just copy_prop, we use ccp to
 	 compute alignment and nonzero bits.  */

gcc/testsuite/gcc.dg/torture/pr55107.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-additional-options "-fno-split-loops" } */
+/* { dg-additional-options "-fno-split-loops -w" } */
 
 typedef unsigned short uint16_t;
 

gcc/testsuite/gcc.dg/tree-ssa/phi_on_compare-1.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-vrp1" } */
+/* { dg-options "-Ofast -fdump-tree-vrp-thread1" } */
 
 void g (int);
 void g1 (int);
@@ -27,4 +27,4 @@ f (long a, long b, long c, long d, long x)
   g (a);
 }
 
-/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/phi_on_compare-2.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-vrp1" } */
+/* { dg-options "-Ofast -fdump-tree-vrp-thread1" } */
 
 void g (void);
 void g1 (void);
@@ -20,4 +20,4 @@ f (long a, long b, long c, long d, int x)
     }
 }
 
-/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/phi_on_compare-3.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-vrp1" } */
+/* { dg-options "-Ofast -fdump-tree-vrp-thread1" } */
 
 void g (void);
 void g1 (void);
@@ -22,4 +22,4 @@ f (long a, long b, long c, long d, int x)
     }
 }
 
-/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/phi_on_compare-4.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-vrp1" } */
+/* { dg-options "-Ofast -fdump-tree-vrp-thread1" } */
 
 void g (int);
 void g1 (int);
@@ -37,4 +37,4 @@ f (long a, long b, long c, long d, int x)
   g (c + d);
 }
 
-/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Removing basic block" 1 "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr21559.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-evrp-details -fdump-tree-vrp1-details" } */
+/* { dg-options "-O2 -fdump-tree-evrp-details -fdump-tree-vrp-thread1-details" } */
 
 static int blocksize = 4096;
 
@@ -39,6 +39,6 @@ void foo (void)
    statement.  We also realize that the final bytes == 0 test is useless,
    and thread over it.  We also know that toread != 0 is useless when
    entering while loop and thread over it.  */
-/* { dg-final { scan-tree-dump-times "Threaded jump" 3 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 3 "vrp-thread1" } } */
 
 

gcc/testsuite/gcc.dg/tree-ssa/pr59597.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-vrp1-details" } */
+/* { dg-options "-Ofast -fdump-tree-vrp-thread1-details" } */
 
 typedef unsigned short u16;
 typedef unsigned char u8;
@@ -56,6 +56,11 @@ main (int argc, char argv[])
   return crc;
 }
 
-/* { dg-final { scan-tree-dump-times "Registering jump thread" 3 "vrp1" } } */
+/* Previously we had 3 jump threads, but one of them crossed loops.
-/* { dg-final { scan-tree-dump-not "joiner" "vrp1" } } */
+   The reason the old threader was allowing it, was because there was
-/* { dg-final { scan-tree-dump-times "Threaded jump" 3 "vrp1" } } */
+   an ASSERT_EXPR getting in the way.  Without the ASSERT_EXPR, we
+   have an empty pre-header block as the final block in the thread,
+   which the threader will simply join with the next block which *is*
+   in a different loop.  */
+/* { dg-final { scan-tree-dump-times "Registering jump thread" 2 "vrp-thread1" } } */
+/* { dg-final { scan-tree-dump-not "joiner" "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr61839_1.c

@@ -1,6 +1,6 @@
 /* PR tree-optimization/61839.  */
 /* { dg-do run } */
-/* { dg-options "-O2 -fdump-tree-vrp1 -fdisable-tree-evrp -fdump-tree-optimized -fdisable-tree-ethread -fdisable-tree-thread1" } */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1 -fdisable-tree-evrp -fdump-tree-optimized -fdisable-tree-ethread -fdisable-tree-thread1" } */
 /* { dg-require-effective-target int32plus } */
 
 __attribute__ ((noinline))
@@ -38,7 +38,11 @@ int main ()
 }
 
 /* Scan for c = 972195717) >> [0, 1] in function foo.  */
-/* { dg-final { scan-tree-dump-times "486097858 : 972195717" 1  "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "486097858 : 972195717" 1  "vrp-thread1" } } */
+
+/* Previously we were checking for two ?: with constant PHI arguments,
+   but now we collapse them into one.  */
 /* Scan for c = 972195717) >> [2, 3] in function bar.  */
-/* { dg-final { scan-tree-dump-times "243048929 : 121524464" 2  "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "243048929 : 121524464" 1  "vrp-thread1" } } */
+
 /* { dg-final { scan-tree-dump-times "486097858" 0  "optimized" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr61839_3.c

@@ -1,6 +1,6 @@
 /* PR tree-optimization/61839.  */
 /* { dg-do run } */
-/* { dg-options "-O2 -fdump-tree-vrp1 -fdump-tree-optimized -fdisable-tree-ethread -fdisable-tree-thread1" } */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1 -fdump-tree-optimized -fdisable-tree-ethread -fdisable-tree-thread1" } */
 
 __attribute__ ((noinline))
 int foo (int a, unsigned b)
@@ -22,5 +22,5 @@ int main ()
 }
 
 /* Scan for c [12, 13] << 8 in function foo.  */
-/* { dg-final { scan-tree-dump-times "3072 : 3328" 2  "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "3072 : 3328" 1  "vrp-thread1" } } */
 /* { dg-final { scan-tree-dump-times "3072" 0  "optimized" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr71437.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-ffast-math -O3 -fdump-tree-vrp1-details" } */
+/* { dg-options "-ffast-math -O3 -fdump-tree-vrp-thread1-details" } */
 
 int I = 50, J = 50;
 int S, L;
@@ -39,4 +39,4 @@ void foo (int K)
 	bar (LD, SD);
     }
 }
-/* { dg-final { scan-tree-dump-times "Threaded jump " 2 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Threaded jump " 2 "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-11.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-dom2-details --param logical-op-non-short-circuit=1 -fdisable-tree-thread1 -fdisable-tree-thread2" } */
+/* { dg-options "-O2 -fdump-tree-dom2-details --param logical-op-non-short-circuit=1 -fdisable-tree-thread1 -fdisable-tree-thread2 -fdisable-tree-vrp-thread1 " } */
 
 static int *bb_ticks;
 extern void frob (void);

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-16.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-dom2-details -w --param logical-op-non-short-circuit=1" } */
+/* { dg-options "-O2 -fdump-tree-dom2-details -w --param logical-op-non-short-circuit=1 -fdisable-tree-vrp-thread1" } */
 unsigned char
 validate_subreg (unsigned int offset, unsigned int isize, unsigned int osize, int zz, int qq)
 {

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-18.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */ 
-/* { dg-options "-O2 -fdump-tree-vrp1-details -fdump-tree-thread1-details -std=gnu89 --param logical-op-non-short-circuit=0" } */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1-details -std=gnu89 --param logical-op-non-short-circuit=0" } */
 
 #include "ssa-dom-thread-4.c"
 
@@ -24,4 +24,4 @@
 
 /* There used to be 6 jump threads found by thread1, but they all
    depended on threading through distinct loops in ethread.  */
-/* { dg-final { scan-tree-dump-times "Threaded" 2 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Threaded" 2 "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-2a.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */ 
-/* { dg-options "-O2 -fdump-tree-vrp1-stats -fdump-tree-dom2-stats" } */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1-stats -fdump-tree-dom2-stats" } */
 
 void bla();
 
@@ -16,6 +16,6 @@ void thread_entry_through_header (void)
 
 /* There's a single jump thread that should be handled by the VRP
    jump threading pass.  */
-/* { dg-final { scan-tree-dump-times "Jumps threaded: 1" 1 "vrp1"} } */
+/* { dg-final { scan-tree-dump-times "Jumps threaded: 1" 1 "vrp-thread1"} } */
-/* { dg-final { scan-tree-dump-times "Jumps threaded: 2" 0 "vrp1"} } */
+/* { dg-final { scan-tree-dump-times "Jumps threaded: 2" 0 "vrp-thread1"} } */
 /* { dg-final { scan-tree-dump-not "Jumps threaded" "dom2"} } */

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-4.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */ 
-/* { dg-options "-O2 -fdump-tree-vrp1-details -fdump-tree-dom2-details -std=gnu89 --param logical-op-non-short-circuit=1" } */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1-details -fdump-tree-dom2-details -std=gnu89 --param logical-op-non-short-circuit=1" } */
 struct bitmap_head_def;
 typedef struct bitmap_head_def *bitmap;
 typedef const struct bitmap_head_def *const_bitmap;
@@ -58,4 +58,5 @@ bitmap_ior_and_compl (bitmap dst, const_bitmap a, const_bitmap b,
    code we missed the edge when the first conditional is false
    (b_elt is zero, which means the second conditional is always
    zero.  VRP1 catches all three.  */
-/* { dg-final { scan-tree-dump-times "Threaded" 3 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Registering jump thread" 2 "vrp-thread1" } } */
+/* { dg-final { scan-tree-dump-times "Path crosses loops" 1 "vrp-thread1" } } */

gcc/testsuite/gcc.dg/tree-ssa/ssa-thread-14.c

@@ -1,7 +1,7 @@
 /* { dg-do compile } */
-/* { dg-additional-options "-O2 -fdump-tree-vrp-details --param logical-op-non-short-circuit=1" }  */
+/* { dg-additional-options "-O2 -fdump-tree-vrp-thread1-details --param logical-op-non-short-circuit=1" }  */
 /* { dg-additional-options "-fdisable-tree-thread1" } */
-/* { dg-final { scan-tree-dump-times "Threaded jump" 8 "vrp1" } }  */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 8 "vrp-thread1" } }  */
 
 void foo (void);
 void bar (void);

gcc/testsuite/gcc.dg/tree-ssa/ssa-vrp-thread-1.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-vrp1-details -fdelete-null-pointer-checks" } */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1-details -fdelete-null-pointer-checks" } */
 /* { dg-skip-if "" keeps_null_pointer_checks } */
 
 void oof (void);
@@ -29,5 +29,5 @@ build_omp_regions_1 (basic_block bb, struct omp_region *parent,
 
 /* ARM Cortex-M defined LOGICAL_OP_NON_SHORT_CIRCUIT to false,
    so skip below test.  */
-/* { dg-final { scan-tree-dump-times "Threaded" 1 "vrp1" { target { ! arm_cortex_m } } } } */
+/* { dg-final { scan-tree-dump-times "Threaded" 1 "vrp-thread1" { target { ! arm_cortex_m } } } } */
 

gcc/testsuite/gcc.dg/tree-ssa/vrp106.c

@@ -1,6 +1,6 @@
 /* PR tree-optimization/18046  */
-/* { dg-options "-O2 -fdump-tree-vrp1-details" }  */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1-details" }  */
-/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp1" } }  */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp-thread1" } }  */
 /* During VRP we expect to thread the true arm of the conditional through the switch
    and to the BB that corresponds to the 7 ... 9 case label.  */
 extern void foo (void);

gcc/testsuite/gcc.dg/tree-ssa/vrp55.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-vrp1-blocks-vops-details -fdelete-null-pointer-checks" } */
+/* { dg-options "-O2 -fdump-tree-vrp-thread1-blocks-vops-details -fdelete-null-pointer-checks" } */
 
 void arf (void);
 
@@ -12,6 +12,6 @@ fu (char *p, int x)
     arf ();
 }
 
-/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp1" { target { ! keeps_null_pointer_checks } } } } */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp-thread1" { target { ! keeps_null_pointer_checks } } } } */
-/* { dg-final { scan-tree-dump-times "Threaded jump" 0 "vrp1" { target {   keeps_null_pointer_checks } } } } */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 0 "vrp-thread1" { target {   keeps_null_pointer_checks } } } } */
 

gcc/tree-pass.h

@@ -462,6 +462,7 @@ extern gimple_opt_pass *make_pass_copy_prop (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_isolate_erroneous_paths (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_early_vrp (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_vrp (gcc::context *ctxt);
+extern gimple_opt_pass *make_pass_vrp_threader (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_uncprop (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_return_slot (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_reassoc (gcc::context *ctxt);

gcc/tree-ssa-threadedge.c

@@ -39,6 +39,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "vr-values.h"
 #include "gimple-ssa-evrp-analyze.h"
 #include "gimple-range.h"
+#include "gimple-range-path.h"
 
 /* To avoid code explosion due to jump threading, we limit the
    number of statements we are going to copy.  This variable
@@ -1397,3 +1398,73 @@ jt_state::register_equivs_stmt (gimple *stmt, basic_block bb,
     register_equiv (gimple_get_lhs (stmt), cached_lhs,
 		    /*update_range=*/false);
 }
+
+// Hybrid threader implementation.
+
+
+void
+hybrid_jt_state::register_equivs_stmt (gimple *, basic_block, jt_simplifier *)
+{
+  // Ranger has no need to simplify anything to improve equivalences.
+}
+
+hybrid_jt_simplifier::hybrid_jt_simplifier (gimple_ranger *r,
+					    path_range_query *q)
+{
+  m_ranger = r;
+  m_query = q;
+}
+
+tree
+hybrid_jt_simplifier::simplify (gimple *stmt, gimple *, basic_block,
+				jt_state *state)
+{
+  int_range_max r;
+
+  compute_ranges_from_state (stmt, state);
+
+  if (gimple_code (stmt) == GIMPLE_COND
+      || gimple_code (stmt) == GIMPLE_ASSIGN)
+    {
+      tree ret;
+      if (m_query->range_of_stmt (r, stmt) && r.singleton_p (&ret))
+	return ret;
+    }
+  else if (gimple_code (stmt) == GIMPLE_SWITCH)
+    {
+      gswitch *switch_stmt = dyn_cast <gswitch *> (stmt);
+      tree index = gimple_switch_index (switch_stmt);
+      if (m_query->range_of_expr (r, index, stmt))
+	return find_case_label_range (switch_stmt, &r);
+    }
+  return NULL;
+}
+
+// Use STATE to generate the list of imports needed for the solver,
+// and calculate the ranges along the path.
+
+void
+hybrid_jt_simplifier::compute_ranges_from_state (gimple *stmt, jt_state *state)
+{
+  auto_bitmap imports;
+  gori_compute &gori = m_ranger->gori ();
+
+  state->get_path (m_path);
+
+  // Start with the imports to the final conditional.
+  bitmap_copy (imports, gori.imports (m_path[0]));
+
+  // Add any other interesting operands we may have missed.
+  if (gimple_bb (stmt) != m_path[0])
+    {
+      for (unsigned i = 0; i < gimple_num_ops (stmt); ++i)
+	{
+	  tree op = gimple_op (stmt, i);
+	  if (op
+	      && TREE_CODE (op) == SSA_NAME
+	      && irange::supports_type_p (TREE_TYPE (op)))
+	    bitmap_set_bit (imports, SSA_NAME_VERSION (op));
+	}
+    }
+  m_query->precompute_ranges (m_path, imports);
+}

gcc/tree-ssa-threadedge.h

@@ -53,6 +53,26 @@ public:
   virtual tree simplify (gimple *, gimple *, basic_block, jt_state *) = 0;
 };
 
+class hybrid_jt_state : public jt_state
+{
+private:
+  void register_equivs_stmt (gimple *, basic_block, jt_simplifier *) override;
+};
+
+class hybrid_jt_simplifier : public jt_simplifier
+{
+public:
+  hybrid_jt_simplifier (class gimple_ranger *r, class path_range_query *q);
+
+private:
+  tree simplify (gimple *stmt, gimple *, basic_block, jt_state *) override;
+  void compute_ranges_from_state (gimple *stmt, jt_state *);
+
+  gimple_ranger *m_ranger;
+  path_range_query *m_query;
+  auto_vec<basic_block> m_path;
+};
+
 // This is the high level threader.  The entry point is
 // thread_outgoing_edges(), which calculates and registers paths to be
 // threaded.  When all candidates have been registered,

gcc/tree-vrp.c

@@ -66,6 +66,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "range-op.h"
 #include "value-range-equiv.h"
 #include "gimple-array-bounds.h"
+#include "gimple-range.h"
+#include "gimple-range-path.h"
 #include "tree-ssa-dom.h"
 
 /* Set of SSA names found live during the RPO traversal of the function
@@ -4591,11 +4593,6 @@ execute_vrp (struct function *fun, bool warn_array_bounds_p)
       array_checker.check ();
     }
 
-  /* We must identify jump threading opportunities before we release
-     the datastructures built by VRP.  */
-  vrp_jump_threader threader (fun, &vrp_vr_values);
-  threader.thread_jumps ();
-
   simplify_casted_conds (fun, &vrp_vr_values);
 
   free_numbers_of_iterations_estimates (fun);
@@ -4605,21 +4602,6 @@ execute_vrp (struct function *fun, bool warn_array_bounds_p)
      does not properly handle ASSERT_EXPRs.  */
   assert_engine.remove_range_assertions ();
 
-  /* If we exposed any new variables, go ahead and put them into
-     SSA form now, before we handle jump threading.  This simplifies
-     interactions between rewriting of _DECL nodes into SSA form
-     and rewriting SSA_NAME nodes into SSA form after block
-     duplication and CFG manipulation.  */
-  update_ssa (TODO_update_ssa);
-
-  /* We identified all the jump threading opportunities earlier, but could
-     not transform the CFG at that time.  This routine transforms the
-     CFG and arranges for the dominator tree to be rebuilt if necessary.
-
-     Note the SSA graph update will occur during the normal TODO
-     processing by the pass manager.  */
-  threader.thread_through_all_blocks ();
-
   scev_finalize ();
   loop_optimizer_finalize ();
   return 0;
@@ -4669,3 +4651,124 @@ make_pass_vrp (gcc::context *ctxt)
 {
   return new pass_vrp (ctxt);
 }
+
+// This is the dom walker for the hybrid threader.  The reason this is
+// here, as opposed to the generic threading files, is because the
+// other client would be DOM, and they have their own custom walker.
+
+class hybrid_threader : public dom_walker
+{
+public:
+  hybrid_threader ();
+  ~hybrid_threader ();
+
+  void thread_jumps (function *fun)
+  {
+    walk (fun->cfg->x_entry_block_ptr);
+  }
+  void thread_through_all_blocks ()
+  {
+    m_threader->thread_through_all_blocks (false);
+  }
+
+private:
+  edge before_dom_children (basic_block) override;
+  void after_dom_children (basic_block bb) override;
+
+  hybrid_jt_simplifier *m_simplifier;
+  jump_threader *m_threader;
+  jt_state *m_state;
+  gimple_ranger *m_ranger;
+  path_range_query *m_query;
+};
+
+hybrid_threader::hybrid_threader () : dom_walker (CDI_DOMINATORS, REACHABLE_BLOCKS)
+{
+  loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
+  scev_initialize ();
+  calculate_dominance_info (CDI_DOMINATORS);
+  mark_dfs_back_edges ();
+
+  m_ranger = new gimple_ranger;
+  m_query = new path_range_query (*m_ranger, /*resolve=*/true);
+  m_simplifier = new hybrid_jt_simplifier (m_ranger, m_query);
+  m_state = new hybrid_jt_state;
+  m_threader = new jump_threader (m_simplifier, m_state);
+}
+
+hybrid_threader::~hybrid_threader ()
+{
+  delete m_simplifier;
+  delete m_threader;
+  delete m_state;
+  delete m_ranger;
+
+  scev_finalize ();
+  loop_optimizer_finalize ();
+}
+
+edge
+hybrid_threader::before_dom_children (basic_block bb)
+{
+  gimple_stmt_iterator gsi;
+  int_range<2> r;
+
+  for (gsi = gsi_start_nondebug_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gimple *stmt = gsi_stmt (gsi);
+      m_ranger->range_of_stmt (r, stmt);
+    }
+  return NULL;
+}
+
+void
+hybrid_threader::after_dom_children (basic_block bb)
+{
+  m_threader->thread_outgoing_edges (bb);
+}
+
+static unsigned int
+execute_vrp_threader (function *fun)
+{
+  hybrid_threader threader;
+  threader.thread_jumps (fun);
+  threader.thread_through_all_blocks ();
+  return 0;
+}
+
+namespace {
+
+const pass_data pass_data_vrp_threader =
+{
+  GIMPLE_PASS, /* type */
+  "vrp-thread", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  TV_TREE_VRP, /* tv_id */
+  PROP_ssa, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  ( TODO_cleanup_cfg | TODO_update_ssa ), /* todo_flags_finish */
+};
+
+class pass_vrp_threader : public gimple_opt_pass
+{
+public:
+  pass_vrp_threader (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_vrp_threader, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  opt_pass * clone () { return new pass_vrp_threader (m_ctxt); }
+  virtual bool gate (function *) { return flag_tree_vrp != 0; }
+  virtual unsigned int execute (function *fun)
+    { return execute_vrp_threader (fun); }
+};
+
+} // namespace {
+
+gimple_opt_pass *
+make_pass_vrp_threader (gcc::context *ctxt)
+{
+  return new pass_vrp_threader (ctxt);
+}

libgomp/team.c

@@ -312,7 +312,7 @@ gomp_team_start (void (*fn) (void *), void *data, unsigned nthreads,
 		 unsigned flags, struct gomp_team *team,
 		 struct gomp_taskgroup *taskgroup)
 {
-  struct gomp_thread_start_data *start_data;
+  struct gomp_thread_start_data *start_data = NULL;
   struct gomp_thread *thr, *nthr;
   struct gomp_task *task;
   struct gomp_task_icv *icv;

libgomp/testsuite/libgomp.graphite/force-parallel-4.c

@@ -1,5 +1,5 @@
 /* Autopar with IF conditions.  */
-/* { dg-additional-options "-fdisable-tree-thread1" } */
+/* { dg-additional-options "-fdisable-tree-thread1 -fdisable-tree-vrp-thread1" } */
 
 void abort();
 

libgomp/testsuite/libgomp.graphite/force-parallel-8.c

@@ -1,4 +1,4 @@
-/* { dg-additional-options "-fdisable-tree-thread1" } */
+/* { dg-additional-options "-fdisable-tree-thread1 -fdisable-tree-vrp-thread1" } */
 
 #define N 1500