Re: [PATCH] libgccjit: Add support for bitcasts [PR104071]

[Antoni Boucher <bouanto@zoho.com>]

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Here's the updated patch.

On Fri, 2022-04-08 at 15:22 -0400, David Malcolm wrote:
> On Fri, 2022-01-21 at 18:41 -0500, Antoni Boucher wrote:
> > Hi.
> > Here's the updated patch.
> > 
> 
> Thanks.  Review below:
> 
> [...snip...]
> 
> > diff --git a/gcc/jit/libgccjit.cc b/gcc/jit/libgccjit.cc
> > index 4c352e8c93d..6bf1e1ceee0 100644
> > --- a/gcc/jit/libgccjit.cc
> > +++ b/gcc/jit/libgccjit.cc
> > @@ -2405,6 +2405,34 @@ gcc_jit_context_new_cast (gcc_jit_context
> > *ctxt,
> >    return static_cast <gcc_jit_rvalue *> (ctxt->new_cast (loc,
> > rvalue, type));
> >  }
> >  
> > +/* Public entrypoint.  See description in libgccjit.h.
> > +
> > +   After error-checking, the real work is done by the
> > +   gcc::jit::recording::context::new_bitcast method in jit-
> > recording.c.  */
> > +
> > +gcc_jit_rvalue *
> > +gcc_jit_context_new_bitcast (gcc_jit_context *ctxt,
> > +                            gcc_jit_location *loc,
> > +                            gcc_jit_rvalue *rvalue,
> > +                            gcc_jit_type *type)
> > +{
> > +  RETURN_NULL_IF_FAIL (ctxt, NULL, loc, "NULL context");
> > +  JIT_LOG_FUNC (ctxt->get_logger ());
> > +  /* LOC can be NULL.  */
> > +  RETURN_NULL_IF_FAIL (rvalue, ctxt, loc, "NULL rvalue");
> > +  RETURN_NULL_IF_FAIL (type, ctxt, loc, "NULL type");
> > +  // TODO: check the sizes.
> > +  /*RETURN_NULL_IF_FAIL_PRINTF3 (
> > +    is_valid_cast (rvalue->get_type (), type),
> > +    ctxt, loc,
> > +    "cannot cast %s from type: %s to type: %s",
> > +    rvalue->get_debug_string (),
> > +    rvalue->get_type ()->get_debug_string (),
> > +    type->get_debug_string ());*/
> 
> I think we agreed that we can't check the sizes at this point, so
> this
> commented-out check would be better replaced with a comment
> explaining
> that we have to defer the check to playback time, when we have the
> trees.
> 
> > +
> > +  return static_cast <gcc_jit_rvalue *> (ctxt->new_bitcast (loc,
> > rvalue, type));
> > +}
> > +
> >  /* Public entrypoint.  See description in libgccjit.h.
> >  
> >     After error-checking, the real work is done by the
> 
> [...snip...]
> 
> > diff --git a/gcc/testsuite/jit.dg/test-bitcast.c
> > b/gcc/testsuite/jit.dg/test-bitcast.c
> > new file mode 100644
> > index 00000000000..a092fa117e6
> > --- /dev/null
> > +++ b/gcc/testsuite/jit.dg/test-bitcast.c
> > @@ -0,0 +1,60 @@
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +#include <string.h>
> > +
> > +#include "libgccjit.h"
> > +
> > +#include "harness.h"
> > +
> > +void
> > +create_code (gcc_jit_context *ctxt, void *user_data)
> > +{
> > +  /* Let's try to inject the equivalent of:
> > +int
> > +my_bitcast (double x)
> > +{
> > +   return bitcast(x, int);
> > +}
> > +   */
> > +  gcc_jit_type *int_type =
> > +    gcc_jit_context_get_int_type (ctxt, 4, 1);
> > +  gcc_jit_type *float_type =
> > +    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_FLOAT);
> 
> This uses GCC_JIT_TYPE_FLOAT for the param...
> 
> > +
> > +  gcc_jit_param *x =
> > +    gcc_jit_context_new_param (
> > +      ctxt,
> > +      NULL,
> > +      float_type, "x");
> > +  gcc_jit_param *params[1] = {x};
> > +  gcc_jit_function *func =
> > +    gcc_jit_context_new_function (ctxt,
> > +                                 NULL,
> > +                                 GCC_JIT_FUNCTION_EXPORTED,
> > +                                 int_type,
> > +                                 "my_bitcast",
> > +                                 1, params, 0);
> 
> [..snip...]
> 
> > +
> > +void
> > +verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
> > +{
> > +  typedef int (*my_bitcast_fn_type) (double);
> 
> ...but this uses "double".  Presumably these should agree, and have
> the
> same sizeof as the integer type.
> 
> > +  CHECK_NON_NULL (result);
> > +  my_bitcast_fn_type my_bitcast =
> > +    (my_bitcast_fn_type)gcc_jit_result_get_code (result,
> > "my_bitcast");
> > +  CHECK_NON_NULL (my_bitcast);
> > +  int val = my_bitcast (-5.1298714);
> > +  note ("my_bitcast returned: %d", val);
> > +  CHECK_VALUE (val, 35569201);
> 
> Out of curiosity, is there any particular significance for these
> values?  FWIW I rather like:
>   http://evanw.github.io/float-toy/
> for directly manipulating the bits of floating point numbers.

The given float values, when bitcast to an int, gives the given int
value.

> 
> 
> [...snip...]
> 
> > diff --git a/gcc/toplev.cc b/gcc/toplev.cc
> > index 534da1462e8..bc4921974eb 100644
> > --- a/gcc/toplev.cc
> > +++ b/gcc/toplev.cc
> > @@ -2368,6 +2368,7 @@ toplev::finalize (void)
> >    gcse_c_finalize ();
> >    ipa_cp_c_finalize ();
> >    ira_costs_c_finalize ();
> > +  tree_cc_finalize ();
> >  
> >    /* save_decoded_options uses opts_obstack, so these must
> >       be cleaned up together.  */
> > diff --git a/gcc/tree.cc b/gcc/tree.cc
> > index ae159ee20ce..fe9d9083026 100644
> > --- a/gcc/tree.cc
> > +++ b/gcc/tree.cc
> > @@ -6963,6 +6963,15 @@ build_reference_type (tree to_type)
> >    (HOST_BITS_PER_WIDE_INT > 64 ? HOST_BITS_PER_WIDE_INT : 64)
> >  static GTY(()) tree nonstandard_integer_type_cache[2 *
> > MAX_INT_CACHED_PREC + 2];
> >  
> > +static void
> > +clear_nonstandard_integer_type_cache (void)
> > +{
> > +  for (size_t i = 0 ; i < 2 * MAX_INT_CACHED_PREC + 2 ; i++)
> > +  {
> > +    nonstandard_integer_type_cache[i] = NULL;
> > +  }
> > +}
> > +
> >  /* Builds a signed or unsigned integer type of precision
> > PRECISION.
> >     Used for C bitfields whose precision does not match that of
> >     built-in target types.  */
> > @@ -14565,6 +14574,12 @@ get_attr_nonstring_decl (tree expr, tree
> > *ref)
> >    return NULL_TREE;
> >  }
> >  
> > +void
> > +tree_cc_finalize (void)
> > +{
> > +  clear_nonstandard_integer_type_cache ();
> > +}
> > +
> >  #if CHECKING_P
> >  
> >  namespace selftest {
> > diff --git a/gcc/tree.h b/gcc/tree.h
> > index 30bc53c2996..bf886fc2472 100644
> > --- a/gcc/tree.h
> > +++ b/gcc/tree.h
> > @@ -5385,6 +5385,7 @@ extern bool real_minus_onep (const_tree);
> >  extern void init_ttree (void);
> >  extern void build_common_tree_nodes (bool);
> >  extern void build_common_builtin_nodes (void);
> > +extern void tree_cc_finalize (void);
> >  extern tree build_nonstandard_integer_type (unsigned
> > HOST_WIDE_INT, int);
> >  extern tree build_nonstandard_boolean_type (unsigned
> > HOST_WIDE_INT);
> >  extern tree build_range_type (tree, tree, tree);
> 
> Looks OK to me, but am not officially a maintainer of these parts.
> 
> LGTM with those nits fixed - for next stage 1, or for trunk now if
> the
> release maintainers are OK with it.
> 
> Thanks again for the patch, and sorry about the belated review.
> 
> Dave
> 
> 
> 


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From 195879c135925a2bc2d53374716dc4b57c79d843 Mon Sep 17 00:00:00 2001
From: Antoni Boucher <bouanto@zoho.com>
Date: Wed, 9 Jun 2021 18:29:14 -0400
Subject: [PATCH] libgccjit: Add support for bitcasts [PR104071]

2022-04-09  Antoni Boucher <bouanto@zoho.com>

gcc/jit/
	PR jit/104071
	* docs/topics/compatibility.rst (LIBGCCJIT_ABI_21): New ABI tag.
	* docs/topics/expressions.rst: Add documentation for the
	function gcc_jit_context_new_bitcast.
	* jit-playback.cc: New function (new_bitcast).
	* jit-playback.h: New function (new_bitcast).
	* jit-recording.cc: New functions (new_bitcast,
	bitcast::replay_into, bitcast::visit_children,
	bitcast::make_debug_string, bitcast::write_reproducer).
	* jit-recording.h: New class (bitcast) and new function
	(new_bitcast, bitcast::replay_into, bitcast::visit_children,
	bitcast::make_debug_string, bitcast::write_reproducer,
	bitcast::get_precedence).
	* libgccjit.cc: New function (gcc_jit_context_new_bitcast)
	* libgccjit.h: New function (gcc_jit_context_new_bitcast)
	* libgccjit.map (LIBGCCJIT_ABI_21): New ABI tag.

gcc/testsuite/
	PR jit/104071
	* jit.dg/all-non-failing-tests.h: Add new test-bitcast.
	* jit.dg/test-bitcast.c: New test.
	* jit.dg/test-error-bad-bitcast.c: New test.
	* jit.dg/test-error-bad-bitcast2.c: New test.

gcc/
	PR jit/104071
	* toplev.cc: Call the new function tree_cc_finalize in
	toplev::finalize.
	* tree.cc: New functions (clear_nonstandard_integer_type_cache
	and tree_cc_finalize) to clear the cache of non-standard integer
	types to avoid having issues with some optimizations of
	bitcast where the SSA_NAME will have a size of a cached
	integer type that should have been invalidated, causing a
	comparison of integer constant to fail.
	* tree.h: New function (tree_cc_finalize).
---
 gcc/jit/docs/topics/compatibility.rst         |  9 +++
 gcc/jit/docs/topics/expressions.rst           | 19 ++++++
 gcc/jit/jit-playback.cc                       | 27 ++++++++
 gcc/jit/jit-playback.h                        |  5 ++
 gcc/jit/jit-recording.cc                      | 66 +++++++++++++++++++
 gcc/jit/jit-recording.h                       | 32 +++++++++
 gcc/jit/libgccjit.cc                          | 22 +++++++
 gcc/jit/libgccjit.h                           | 15 +++++
 gcc/jit/libgccjit.map                         |  9 +++
 gcc/testsuite/jit.dg/all-non-failing-tests.h  | 10 +++
 gcc/testsuite/jit.dg/test-bitcast.c           | 60 +++++++++++++++++
 gcc/testsuite/jit.dg/test-error-bad-bitcast.c | 62 +++++++++++++++++
 .../jit.dg/test-error-bad-bitcast2.c          | 62 +++++++++++++++++
 gcc/toplev.cc                                 |  1 +
 gcc/tree.cc                                   | 15 +++++
 gcc/tree.h                                    |  1 +
 16 files changed, 415 insertions(+)
 create mode 100644 gcc/testsuite/jit.dg/test-bitcast.c
 create mode 100644 gcc/testsuite/jit.dg/test-error-bad-bitcast.c
 create mode 100644 gcc/testsuite/jit.dg/test-error-bad-bitcast2.c

diff --git a/gcc/jit/docs/topics/compatibility.rst b/gcc/jit/docs/topics/compatibility.rst
index 16cebe31a10..610d9dc175f 100644
--- a/gcc/jit/docs/topics/compatibility.rst
+++ b/gcc/jit/docs/topics/compatibility.rst
@@ -302,3 +302,12 @@ thread-local storage model of a variable:
 section of a variable:
 
   * :func:`gcc_jit_lvalue_set_link_section`
+
+.. _LIBGCCJIT_ABI_21:
+
+``LIBGCCJIT_ABI_21``
+-----------------------
+``LIBGCCJIT_ABI_21`` covers the addition of an API entrypoint to bitcast a
+value from one type to another:
+
+  * :func:`gcc_jit_context_new_bitcast`
diff --git a/gcc/jit/docs/topics/expressions.rst b/gcc/jit/docs/topics/expressions.rst
index 791a20398ca..e0b6f426aee 100644
--- a/gcc/jit/docs/topics/expressions.rst
+++ b/gcc/jit/docs/topics/expressions.rst
@@ -649,6 +649,25 @@ Type-coercion
      * int <-> bool
      * P*  <-> Q*, for pointer types P and Q
 
+.. function:: gcc_jit_rvalue *\
+              gcc_jit_context_new_bitcast (gcc_jit_context *ctxt,\
+                                           gcc_jit_location *loc,\
+                                           gcc_jit_rvalue *rvalue,\
+                                           gcc_jit_type *type)
+
+   Given an rvalue of T, bitcast it to another type, meaning that this will
+   generate a new rvalue by interpreting the bits of ``rvalue`` to the layout
+   of ``type``.
+
+   The type of rvalue must be the same size as the size of ``type``.
+
+   This entrypoint was added in :ref:`LIBGCCJIT_ABI_21`; you can test for
+   its presence using
+
+   .. code-block:: c
+
+      #ifdef LIBGCCJIT_HAVE_gcc_jit_context_new_bitcast
+
 Lvalues
 -------
 
diff --git a/gcc/jit/jit-playback.cc b/gcc/jit/jit-playback.cc
index d1835c79863..d2efae1c163 100644
--- a/gcc/jit/jit-playback.cc
+++ b/gcc/jit/jit-playback.cc
@@ -1390,6 +1390,33 @@ new_cast (playback::location *loc,
   return new rvalue (this, t_cast);
 }
 
+playback::rvalue *
+playback::context::
+new_bitcast (location *loc,
+		       rvalue *expr,
+		       type *type_)
+{
+  tree expr_size = TYPE_SIZE (expr->get_type ()->as_tree ());
+  tree type_size = TYPE_SIZE (type_->as_tree ());
+  tree t_expr = expr->as_tree ();
+  tree t_dst_type = type_->as_tree ();
+  if (expr_size != type_size)
+  {
+    active_playback_ctxt->add_error (loc,
+      "bitcast with types of different sizes");
+    fprintf (stderr, "input expression (size: %ld):\n",
+      tree_to_uhwi (expr_size));
+    debug_tree (t_expr);
+    fprintf (stderr, "requested type (size: %ld):\n",
+      tree_to_uhwi (type_size));
+    debug_tree (t_dst_type);
+  }
+  tree t_bitcast = build1 (VIEW_CONVERT_EXPR, t_dst_type, t_expr);
+  if (loc)
+    set_tree_location (t_bitcast, loc);
+  return new rvalue (this, t_bitcast);
+}
+
 /* Construct a playback::lvalue instance (wrapping a tree) for an
    array access.  */
 
diff --git a/gcc/jit/jit-playback.h b/gcc/jit/jit-playback.h
index c93d7055d43..5b107be9d69 100644
--- a/gcc/jit/jit-playback.h
+++ b/gcc/jit/jit-playback.h
@@ -180,6 +180,11 @@ public:
 	    rvalue *expr,
 	    type *type_);
 
+  rvalue *
+  new_bitcast (location *loc,
+	       rvalue *expr,
+	       type *type_);
+
   lvalue *
   new_array_access (location *loc,
 		    rvalue *ptr,
diff --git a/gcc/jit/jit-recording.cc b/gcc/jit/jit-recording.cc
index 1e3fadfacd7..e1029086da8 100644
--- a/gcc/jit/jit-recording.cc
+++ b/gcc/jit/jit-recording.cc
@@ -1242,6 +1242,22 @@ recording::context::new_cast (recording::location *loc,
   return result;
 }
 
+/* Create a recording::bitcast instance and add it to this context's list
+   of mementos.
+
+   Implements the post-error-checking part of
+   gcc_jit_context_new_bitcast.  */
+
+recording::rvalue *
+recording::context::new_bitcast (location *loc,
+				 rvalue *expr,
+				 type *type_)
+{
+  recording::rvalue *result = new bitcast (this, loc, expr, type_);
+  record (result);
+  return result;
+}
+
 /* Create a recording::call instance and add it to this context's list
    of mementos.
 
@@ -5740,6 +5756,56 @@ recording::cast::write_reproducer (reproducer &r)
 	   r.get_identifier_as_type (get_type ()));
 }
 
+/* Implementation of pure virtual hook recording::memento::replay_into
+   for recording::bitcast.  */
+
+void
+recording::bitcast::replay_into (replayer *r)
+{
+  set_playback_obj (r->new_bitcast (playback_location (r, m_loc),
+				    m_rvalue->playback_rvalue (),
+				    get_type ()->playback_type ()));
+}
+
+/* Implementation of pure virtual hook recording::rvalue::visit_children
+   for recording::bitcast.  */
+void
+recording::bitcast::visit_children (rvalue_visitor *v)
+{
+  v->visit (m_rvalue);
+}
+
+/* Implementation of recording::memento::make_debug_string for
+   casts.  */
+
+recording::string *
+recording::bitcast::make_debug_string ()
+{
+  enum precedence prec = get_precedence ();
+  return string::from_printf (m_ctxt,
+			      "bitcast(%s, %s)",
+			      m_rvalue->get_debug_string_parens (prec),
+			      get_type ()->get_debug_string ());
+}
+
+/* Implementation of recording::memento::write_reproducer for casts.  */
+
+void
+recording::bitcast::write_reproducer (reproducer &r)
+{
+  const char *id = r.make_identifier (this, "rvalue");
+  r.write ("  gcc_jit_rvalue *%s =\n"
+	   "    gcc_jit_context_new_bitcast (%s,\n"
+	   "                                 %s, /* gcc_jit_location *loc */\n"
+	   "                                 %s, /* gcc_jit_rvalue *rvalue */\n"
+	   "                                 %s); /* gcc_jit_type *type */\n",
+	   id,
+	   r.get_identifier (get_context ()),
+	   r.get_identifier (m_loc),
+	   r.get_identifier_as_rvalue (m_rvalue),
+	   r.get_identifier_as_type (get_type ()));
+}
+
 /* The implementation of class gcc::jit::recording::base_call.  */
 
 /* The constructor for gcc::jit::recording::base_call.  */
diff --git a/gcc/jit/jit-recording.h b/gcc/jit/jit-recording.h
index 846d65cb202..ed03b3a24c8 100644
--- a/gcc/jit/jit-recording.h
+++ b/gcc/jit/jit-recording.h
@@ -205,6 +205,11 @@ public:
 	    rvalue *expr,
 	    type *type_);
 
+  rvalue *
+  new_bitcast (location *loc,
+	       rvalue *expr,
+	       type *type_);
+
   lvalue *
   new_array_access (location *loc,
 		    rvalue *ptr,
@@ -1691,6 +1696,33 @@ private:
   rvalue *m_rvalue;
 };
 
+class bitcast : public rvalue
+{
+public:
+  bitcast (context *ctxt,
+	   location *loc,
+	   rvalue *a,
+	   type *type_)
+  : rvalue (ctxt, loc, type_),
+    m_rvalue (a)
+  {}
+
+  void replay_into (replayer *r) FINAL OVERRIDE;
+
+  void visit_children (rvalue_visitor *v) FINAL OVERRIDE;
+
+private:
+  string * make_debug_string () FINAL OVERRIDE;
+  void write_reproducer (reproducer &r) FINAL OVERRIDE;
+  enum precedence get_precedence () const FINAL OVERRIDE
+  {
+    return PRECEDENCE_CAST;
+  }
+
+private:
+  rvalue *m_rvalue;
+};
+
 class base_call : public rvalue
 {
  public:
diff --git a/gcc/jit/libgccjit.cc b/gcc/jit/libgccjit.cc
index 4c352e8c93d..3535203975c 100644
--- a/gcc/jit/libgccjit.cc
+++ b/gcc/jit/libgccjit.cc
@@ -2405,6 +2405,28 @@ gcc_jit_context_new_cast (gcc_jit_context *ctxt,
   return static_cast <gcc_jit_rvalue *> (ctxt->new_cast (loc, rvalue, type));
 }
 
+/* Public entrypoint.  See description in libgccjit.h.
+
+   After error-checking, the real work is done by the
+   gcc::jit::recording::context::new_bitcast method in jit-recording.c.  */
+
+gcc_jit_rvalue *
+gcc_jit_context_new_bitcast (gcc_jit_context *ctxt,
+			     gcc_jit_location *loc,
+			     gcc_jit_rvalue *rvalue,
+			     gcc_jit_type *type)
+{
+  RETURN_NULL_IF_FAIL (ctxt, NULL, loc, "NULL context");
+  JIT_LOG_FUNC (ctxt->get_logger ());
+  /* LOC can be NULL.  */
+  RETURN_NULL_IF_FAIL (rvalue, ctxt, loc, "NULL rvalue");
+  RETURN_NULL_IF_FAIL (type, ctxt, loc, "NULL type");
+  /* We cannot check if the size of rvalue matches the size of type here, so
+   we'll do it at playback. */
+
+  return static_cast <gcc_jit_rvalue *> (ctxt->new_bitcast (loc, rvalue, type));
+}
+
 /* Public entrypoint.  See description in libgccjit.h.
 
    After error-checking, the real work is done by the
diff --git a/gcc/jit/libgccjit.h b/gcc/jit/libgccjit.h
index 2a5ffacb1fe..960e4f4261e 100644
--- a/gcc/jit/libgccjit.h
+++ b/gcc/jit/libgccjit.h
@@ -1206,6 +1206,21 @@ gcc_jit_context_new_cast (gcc_jit_context *ctxt,
 			  gcc_jit_rvalue *rvalue,
 			  gcc_jit_type *type);
 
+/* Reinterpret a value as another type.
+
+#define LIBGCCJIT_HAVE_gcc_jit_context_new_bitcast
+
+   The types must be of the same size.
+
+   This API entrypoint was added in LIBGCCJIT_ABI_21; you can test for its
+   presence using
+     #ifdef LIBGCCJIT_HAVE_gcc_jit_context_new_bitcast  */
+extern gcc_jit_rvalue *
+gcc_jit_context_new_bitcast (gcc_jit_context *ctxt,
+			     gcc_jit_location *loc,
+			     gcc_jit_rvalue *rvalue,
+			     gcc_jit_type *type);
+
 extern gcc_jit_lvalue *
 gcc_jit_context_new_array_access (gcc_jit_context *ctxt,
 				  gcc_jit_location *loc,
diff --git a/gcc/jit/libgccjit.map b/gcc/jit/libgccjit.map
index f373fd39ac7..38c355437bf 100644
--- a/gcc/jit/libgccjit.map
+++ b/gcc/jit/libgccjit.map
@@ -238,8 +238,17 @@ LIBGCCJIT_ABI_18 {
 } LIBGCCJIT_ABI_17;
 
 LIBGCCJIT_ABI_19 {
+  global:
     gcc_jit_context_new_array_constructor;
     gcc_jit_context_new_struct_constructor;
     gcc_jit_context_new_union_constructor;
     gcc_jit_global_set_initializer_rvalue;
 } LIBGCCJIT_ABI_18;
+
+LIBGCCJIT_ABI_20 {
+} LIBGCCJIT_ABI_19;
+
+LIBGCCJIT_ABI_21 {
+  global:
+    gcc_jit_context_new_bitcast;
+} LIBGCCJIT_ABI_20;
diff --git a/gcc/testsuite/jit.dg/all-non-failing-tests.h b/gcc/testsuite/jit.dg/all-non-failing-tests.h
index 29afe064db6..656351edce1 100644
--- a/gcc/testsuite/jit.dg/all-non-failing-tests.h
+++ b/gcc/testsuite/jit.dg/all-non-failing-tests.h
@@ -77,6 +77,13 @@
 /* test-builtin-unreachable.c: We don't add this one, since it touches
    the optimization level of the context as a whole.  */
 
+/* test-bitcast.c */
+#define create_code create_code_bitcast
+#define verify_code verify_code_bitcast
+#include "test-bitcast.c"
+#undef create_code
+#undef verify_code
+
 /* test-calling-external-function.c */
 #define create_code create_code_calling_external_function
 #define verify_code verify_code_calling_external_function
@@ -400,6 +407,9 @@ const struct testcase testcases[] = {
   {"builtin-memcpy",
    create_code_builtin_memcpy,
    verify_code_builtin_memcpy},
+  {"bitcast",
+   create_code_bitcast,
+   verify_code_bitcast},
   {"calling_external_function",
    create_code_calling_external_function,
    verify_code_calling_external_function},
diff --git a/gcc/testsuite/jit.dg/test-bitcast.c b/gcc/testsuite/jit.dg/test-bitcast.c
new file mode 100644
index 00000000000..16d889d3abe
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-bitcast.c
@@ -0,0 +1,60 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Let's try to inject the equivalent of:
+int
+my_bitcast (float x)
+{
+   return bitcast(x, int);
+}
+   */
+  gcc_jit_type *int_type =
+    gcc_jit_context_get_int_type (ctxt, 4, 1);
+  gcc_jit_type *float_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_FLOAT);
+
+  gcc_jit_param *x =
+    gcc_jit_context_new_param (
+      ctxt,
+      NULL,
+      float_type, "x");
+  gcc_jit_param *params[1] = {x};
+  gcc_jit_function *func =
+    gcc_jit_context_new_function (ctxt,
+				  NULL,
+				  GCC_JIT_FUNCTION_EXPORTED,
+				  int_type,
+				  "my_bitcast",
+				  1, params, 0);
+
+  gcc_jit_block *initial =
+    gcc_jit_function_new_block (func, "initial");
+
+  gcc_jit_block_end_with_return(initial, NULL,
+    gcc_jit_context_new_bitcast(ctxt,
+        NULL,
+        gcc_jit_param_as_rvalue(x),
+        int_type
+    ));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  typedef int (*my_bitcast_fn_type) (float);
+  CHECK_NON_NULL (result);
+  my_bitcast_fn_type my_bitcast =
+    (my_bitcast_fn_type)gcc_jit_result_get_code (result, "my_bitcast");
+  CHECK_NON_NULL (my_bitcast);
+  int val = my_bitcast (-5.1298714);
+  note ("my_bitcast returned: %d", val);
+  CHECK_VALUE (val, 35569201);
+}
diff --git a/gcc/testsuite/jit.dg/test-error-bad-bitcast.c b/gcc/testsuite/jit.dg/test-error-bad-bitcast.c
new file mode 100644
index 00000000000..642890605ad
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-error-bad-bitcast.c
@@ -0,0 +1,62 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Let's try to inject the equivalent of:
+
+     int
+     test_fn ()
+     {
+       char f[4096];
+       return bitcast(f, int);
+     }
+
+     and verify that the API complains about the bad cast.
+  */
+  gcc_jit_type *int_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
+  gcc_jit_type *char_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_CHAR);
+
+
+  gcc_jit_type *array_type =
+    gcc_jit_context_new_array_type (ctxt, NULL, char_type, 4096);
+
+  gcc_jit_function *test_fn =
+    gcc_jit_context_new_function (ctxt, NULL,
+                                  GCC_JIT_FUNCTION_EXPORTED,
+                                  int_type,
+                                  "test_fn",
+                                  0, NULL,
+                                  0);
+  gcc_jit_lvalue *f =
+    gcc_jit_function_new_local (
+      test_fn,
+      NULL,
+      array_type, "f");
+
+  gcc_jit_block *block = gcc_jit_function_new_block (test_fn, NULL);
+
+  gcc_jit_block_end_with_return (
+    block, NULL,
+    gcc_jit_context_new_bitcast (ctxt, NULL,
+			      gcc_jit_lvalue_as_rvalue (f),
+			      int_type));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  CHECK_VALUE (result, NULL);
+
+  /* Verify that the correct error message was emitted.  */
+  CHECK_STRING_VALUE (gcc_jit_context_get_first_error (ctxt),
+		      "bitcast with types of different sizes");
+}
+
diff --git a/gcc/testsuite/jit.dg/test-error-bad-bitcast2.c b/gcc/testsuite/jit.dg/test-error-bad-bitcast2.c
new file mode 100644
index 00000000000..602ae407076
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-error-bad-bitcast2.c
@@ -0,0 +1,62 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Let's try to inject the equivalent of:
+
+     char[4096]
+     test_fn ()
+     {
+       int f;
+       return bitcast(f, char[4096]);
+     }
+
+     and verify that the API complains about the bad cast.
+  */
+  gcc_jit_type *int_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
+  gcc_jit_type *char_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_CHAR);
+
+
+  gcc_jit_type *array_type =
+    gcc_jit_context_new_array_type (ctxt, NULL, char_type, 4096);
+
+  gcc_jit_function *test_fn =
+    gcc_jit_context_new_function (ctxt, NULL,
+                                  GCC_JIT_FUNCTION_EXPORTED,
+                                  array_type,
+                                  "test_fn",
+                                  0, NULL,
+                                  0);
+  gcc_jit_lvalue *f =
+    gcc_jit_function_new_local (
+      test_fn,
+      NULL,
+      int_type, "f");
+
+  gcc_jit_block *block = gcc_jit_function_new_block (test_fn, NULL);
+
+  gcc_jit_block_end_with_return (
+    block, NULL,
+    gcc_jit_context_new_bitcast (ctxt, NULL,
+			      gcc_jit_lvalue_as_rvalue (f),
+			      array_type));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  CHECK_VALUE (result, NULL);
+
+  /* Verify that the correct error message was emitted.  */
+  CHECK_STRING_VALUE (gcc_jit_context_get_first_error (ctxt),
+		      "bitcast with types of different sizes");
+}
+
diff --git a/gcc/toplev.cc b/gcc/toplev.cc
index 534da1462e8..bc4921974eb 100644
--- a/gcc/toplev.cc
+++ b/gcc/toplev.cc
@@ -2368,6 +2368,7 @@ toplev::finalize (void)
   gcse_c_finalize ();
   ipa_cp_c_finalize ();
   ira_costs_c_finalize ();
+  tree_cc_finalize ();
 
   /* save_decoded_options uses opts_obstack, so these must
      be cleaned up together.  */
diff --git a/gcc/tree.cc b/gcc/tree.cc
index ae159ee20ce..fe9d9083026 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -6963,6 +6963,15 @@ build_reference_type (tree to_type)
   (HOST_BITS_PER_WIDE_INT > 64 ? HOST_BITS_PER_WIDE_INT : 64)
 static GTY(()) tree nonstandard_integer_type_cache[2 * MAX_INT_CACHED_PREC + 2];
 
+static void
+clear_nonstandard_integer_type_cache (void)
+{
+  for (size_t i = 0 ; i < 2 * MAX_INT_CACHED_PREC + 2 ; i++)
+  {
+    nonstandard_integer_type_cache[i] = NULL;
+  }
+}
+
 /* Builds a signed or unsigned integer type of precision PRECISION.
    Used for C bitfields whose precision does not match that of
    built-in target types.  */
@@ -14565,6 +14574,12 @@ get_attr_nonstring_decl (tree expr, tree *ref)
   return NULL_TREE;
 }
 
+void
+tree_cc_finalize (void)
+{
+  clear_nonstandard_integer_type_cache ();
+}
+
 #if CHECKING_P
 
 namespace selftest {
diff --git a/gcc/tree.h b/gcc/tree.h
index 30bc53c2996..bf886fc2472 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -5385,6 +5385,7 @@ extern bool real_minus_onep (const_tree);
 extern void init_ttree (void);
 extern void build_common_tree_nodes (bool);
 extern void build_common_builtin_nodes (void);
+extern void tree_cc_finalize (void);
 extern tree build_nonstandard_integer_type (unsigned HOST_WIDE_INT, int);
 extern tree build_nonstandard_boolean_type (unsigned HOST_WIDE_INT);
 extern tree build_range_type (tree, tree, tree);
-- 
2.26.2.7.g19db9cfb68.dirty