[gcc(refs/users/aoliva/heads/testme)] [PR103024, PR103530] support throwing compares and non-boolean types

[Alexandre Oliva <aoliva@gcc.gnu.org>]

https://gcc.gnu.org/g:623fabc300ffadb03defb49bfec0ca5d48356508

commit 623fabc300ffadb03defb49bfec0ca5d48356508
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Sat Dec 4 03:06:00 2021 -0300

    [PR103024,PR103530] support throwing compares and non-boolean types

Diff:
---
 gcc/gimple-harden-conditionals.cc | 74 ++++++++++++++++++++++++++++++++++++---
 gcc/testsuite/g++.dg/pr103024.C   | 12 +++++++
 gcc/testsuite/g++.dg/pr103530.C   | 27 ++++++++++++++
 3 files changed, 109 insertions(+), 4 deletions(-)

diff --git a/gcc/gimple-harden-conditionals.cc b/gcc/gimple-harden-conditionals.cc
index cfa2361d65b..ee332f9e8db 100644
--- a/gcc/gimple-harden-conditionals.cc
+++ b/gcc/gimple-harden-conditionals.cc
@@ -33,6 +33,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "basic-block.h"
 #include "cfghooks.h"
 #include "cfgloop.h"
+#include "tree-eh.h"
 #include "diagnostic.h"
 #include "intl.h"
 
@@ -304,6 +305,24 @@ make_pass_harden_conditional_branches (gcc::context *ctxt)
   return new pass_harden_conditional_branches (ctxt);
 }
 
+/* Return the fallthru edge of a block whose other edge is an EH
+   edge.  */
+static inline edge
+non_eh_succ_edge (basic_block bb)
+{
+  gcc_checking_assert (EDGE_COUNT (bb->succs) == 2);
+
+  edge ret = find_fallthru_edge (bb->succs);
+
+  int eh_idx = EDGE_SUCC (bb, 0) == ret;
+  edge eh = EDGE_SUCC (bb, eh_idx);
+
+  gcc_checking_assert (!(ret->flags & EDGE_EH)
+		       && (eh->flags & EDGE_EH));
+
+  return ret;
+}
+
 /* Harden boolean-yielding compares in FUN.  */
 
 unsigned int
@@ -394,7 +413,11 @@ pass_harden_compares::execute (function *fun)
 	if (VECTOR_TYPE_P (TREE_TYPE (op1)))
 	  continue;
 
-	gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE);
+	/* useless_type_conversion_p enables conversions from 1-bit
+	   integer types to boolean to be discarded.  */
+	gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+			     || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+				 && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
 
 	tree rhs = copy_ssa_name (lhs);
 
@@ -405,6 +428,20 @@ pass_harden_compares::execute (function *fun)
 	   won't be debug stmts only.  */
 	gsi_next_nondebug (&gsi_split);
 
+	bool throwing_compare_p = stmt_ends_bb_p (asgn);
+	if (throwing_compare_p)
+	  {
+	    basic_block nbb = split_edge (non_eh_succ_edge
+					  (gimple_bb (asgn)));
+	    gsi_split = gsi_start_bb (nbb);
+
+	    if (dump_file)
+	      fprintf (dump_file,
+		       "Splitting non-EH edge from block %i into %i"
+		       " after a throwing compare\n",
+		       gimple_bb (asgn)->index, nbb->index);
+	  }
+
 	bool same_p = (op1 == op2);
 	op1 = detach_value (loc, &gsi_split, op1);
 	op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
@@ -418,17 +455,46 @@ pass_harden_compares::execute (function *fun)
 	if (!gsi_end_p (gsi_split))
 	  {
 	    gsi_prev (&gsi_split);
-	    split_block (bb, gsi_stmt (gsi_split));
+	    basic_block obb = gsi_bb (gsi_split);
+	    basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
 	    gsi_next (&gsi_split);
 	    gcc_checking_assert (gsi_end_p (gsi_split));
 
 	    single_succ_edge (bb)->goto_locus = loc;
 
 	    if (dump_file)
-	      fprintf (dump_file, "Splitting block %i\n", bb->index);
+	      fprintf (dump_file,
+		       "Splitting block %i into %i"
+		       " before the conditional trap branch\n",
+		       obb->index, nbb->index);
+	  }
+
+	/* If the check assignment must end a basic block, we can't
+	   insert the conditional branch in the same block, so split
+	   the block again, and prepare to insert the conditional
+	   branch in the new block.
+
+	   Also assign an EH region to the compare.  Even though it's
+	   unlikely that the hardening compare will throw after the
+	   original compare didn't, the compiler won't even know that
+	   it's the same compare operands, so add the EH edge anyway.  */
+	if (throwing_compare_p)
+	  {
+	    add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
+	    make_eh_edges (asgnck);
+
+	    basic_block nbb = split_edge (non_eh_succ_edge
+					  (gimple_bb (asgnck)));
+	    gsi_split = gsi_start_bb (nbb);
+
+	    if (dump_file)
+	      fprintf (dump_file,
+		       "Splitting non-EH edge from block %i into %i after"
+		       " the newly-inserted reversed throwing compare\n",
+		       gimple_bb (asgnck)->index, nbb->index);
 	  }
 
-	gcc_checking_assert (single_succ_p (bb));
+	gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
 
 	insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
 			       EQ_EXPR, lhs, rhs);
diff --git a/gcc/testsuite/g++.dg/pr103024.C b/gcc/testsuite/g++.dg/pr103024.C
new file mode 100644
index 00000000000..15e68d40213
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr103024.C
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-fnon-call-exceptions -fharden-compares -fsignaling-nans" } */
+
+struct G4ErrorMatrix {
+  G4ErrorMatrix(int);
+  ~G4ErrorMatrix();
+};
+double PropagateError_charge;
+void PropagateError() {
+  G4ErrorMatrix transf(0);
+  int field(PropagateError_charge && field);
+}
diff --git a/gcc/testsuite/g++.dg/pr103530.C b/gcc/testsuite/g++.dg/pr103530.C
new file mode 100644
index 00000000000..726b0eb3427
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr103530.C
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fharden-compares" } */
+
+enum E:bool
+{ E0, E1 };
+
+int x;
+
+E
+baz (E rtt)
+{
+  return rtt == E0 ? E1 : E0;
+}
+
+bool bar ();
+
+void
+foo (E)
+{
+  E a = x ? E1 : E0;
+  if (bar ())
+    if (bar ())
+      {
+	E b = baz (a);
+	foo (b);
+      }
+}