[committed] d: Fix ICE in gimplify_expr, at gimplify.c (PR98277)

[committed] d: Fix ICE in gimplify_expr, at gimplify.c (PR98277)

[Iain Buclaw]

Hi,

This patch fixes an ICE during gimplify_expr for code generated by the D
front-end.  The DMD front-end shouldn't, but can sometimes leak manifest
constants in the AST passed to the code generator.  To prevent this
being an issue, the setting of DECL_INITIAL has been moved to the point
where the CONST_DECL is used, rather than in the declaration handler.

Bootstrapped and regression tested on x86_64-linux-gnu/-m32/-mx32.
Committed to mainline, and backported to the GCC-10 and GCC-9.

Regards
Iain

---
gcc/d/ChangeLog:

	PR d/98277
	* decl.cc (DeclVisitor::visit (VarDeclaration *)): Move setting of
	DECL_INITIAL for manifest constants to ...
	(get_symbol_decl): ... here.

gcc/testsuite/ChangeLog:

	PR d/98277
	* gdc.dg/pr98277.d: New test.
---
 gcc/d/decl.cc                  | 43 +++++++++++++++++-----------------
 gcc/testsuite/gdc.dg/pr98277.d | 13 ++++++++++
 2 files changed, 35 insertions(+), 21 deletions(-)
 create mode 100644 gcc/testsuite/gdc.dg/pr98277.d

diff --git a/gcc/d/decl.cc b/gcc/d/decl.cc
index 218f35838fd..a3db4ae6d89 100644
--- a/gcc/d/decl.cc
+++ b/gcc/d/decl.cc
@@ -653,31 +653,13 @@ public:
 	return;
       }
 
-    /* Do not store variables we cannot take the address of,
-       but keep the values for purposes of debugging.  */
     if (!d->canTakeAddressOf ())
       {
-	/* Don't know if there is a good way to handle instantiations.  */
-	if (d->isInstantiated ())
-	  return;
-
-	/* Cannot make an expression out of a void initializer.  */
-	if (!d->_init || d->_init->isVoidInitializer ())
-	  return;
-
-	tree decl = get_symbol_decl (d);
-	Expression *ie = initializerToExpression (d->_init);
-
-	/* CONST_DECL was initially intended for enumerals and may be used for
-	   scalars in general, but not for aggregates.  Here a non-constant
-	   value is generated anyway so as the CONST_DECL only serves as a
-	   placeholder for the value, however the DECL itself should never be
-	   referenced in any generated code, or passed to the back-end.  */
+	/* Do not store variables we cannot take the address of,
+	   but keep the values for purposes of debugging.  */
 	if (!d->type->isscalar ())
-	  DECL_INITIAL (decl) = build_expr (ie, false);
-	else
 	  {
-	    DECL_INITIAL (decl) = build_expr (ie, true);
+	    tree decl = get_symbol_decl (d);
 	    d_pushdecl (decl);
 	    rest_of_decl_compilation (decl, 1, 0);
 	  }
@@ -1106,6 +1088,25 @@ get_symbol_decl (Declaration *decl)
 
       if (vd->storage_class & STCextern)
 	DECL_EXTERNAL (decl->csym) = 1;
+
+      /* CONST_DECL was initially intended for enumerals and may be used for
+	 scalars in general, but not for aggregates.  Here a non-constant
+	 value is generated anyway so as the CONST_DECL only serves as a
+	 placeholder for the value, however the DECL itself should never be
+	 referenced in any generated code, or passed to the back-end.  */
+      if (vd->storage_class & STCmanifest)
+	{
+	  /* Cannot make an expression out of a void initializer.  */
+	  if (vd->_init && !vd->_init->isVoidInitializer ())
+	    {
+	      Expression *ie = initializerToExpression (vd->_init);
+
+	      if (!vd->type->isscalar ())
+		DECL_INITIAL (decl->csym) = build_expr (ie, false);
+	      else
+		DECL_INITIAL (decl->csym) = build_expr (ie, true);
+	    }
+	}
     }
 
   /* Set the declaration mangled identifier if static.  */
diff --git a/gcc/testsuite/gdc.dg/pr98277.d b/gcc/testsuite/gdc.dg/pr98277.d
new file mode 100644
index 00000000000..d3b859fcbda
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr98277.d
@@ -0,0 +1,13 @@
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98277
+// { dg-do compile }
+
+enum Side
+{
+    left,
+    right
+}
+
+ref int getSide(Side side, ref int left, ref int right)
+{
+    return side == Side.left ? left : right;
+}
-- 
2.27.0