x86: Fix up ix86_atomic_assign_expand_fenv [PR94780]

This function, because it is sometimes called even outside of function
bodies, uses create_tmp_var_raw rather than create_tmp_var.  But in order
for that to work, when first referenced, the VAR_DECLs need to appear in a
TARGET_EXPR so that during gimplification the var gets the right
DECL_CONTEXT and is added to local decls.  Without that, e.g. tree-nested.c
ICEs on those.

2020-04-27  Jakub Jelinek  <jakub@redhat.com>

	PR target/94780
	* config/i386/i386.c (ix86_atomic_assign_expand_fenv): Use
	TARGET_EXPR instead of MODIFY_EXPR for first assignment to
	sw_var, exceptions_var, mxcsr_orig_var and mxcsr_mod_var.

	* gcc.dg/pr94780.c: New test.

(cherry picked from commit 9b8e9006bb35641865358e2df4f6b3ae185b239a)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index c6bc468e36bf07a650d1f8731ce1942acf7908e6..5978e51e8eaf04dd900628c54d9069c7a82482f3 100644 (file)
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -50943,11 +50943,12 @@ ix86_atomic_assign_expand_fenv (tree *hold, tree *clear, tree *update)
       *clear = build_call_expr (fnclex, 0);
       tree sw_var = create_tmp_var_raw (short_unsigned_type_node);
       tree fnstsw_call = build_call_expr (fnstsw, 0);
-      tree sw_mod = build2 (MODIFY_EXPR, short_unsigned_type_node,
-                           sw_var, fnstsw_call);
+      tree sw_mod = build4 (TARGET_EXPR, short_unsigned_type_node, sw_var,
+                           fnstsw_call, NULL_TREE, NULL_TREE);
       tree exceptions_x87 = fold_convert (integer_type_node, sw_var);
-      tree update_mod = build2 (MODIFY_EXPR, integer_type_node,
-                               exceptions_var, exceptions_x87);
+      tree update_mod = build4 (TARGET_EXPR, integer_type_node,
+                               exceptions_var, exceptions_x87,
+                               NULL_TREE, NULL_TREE);
       *update = build2 (COMPOUND_EXPR, integer_type_node,
                        sw_mod, update_mod);
       tree update_fldenv = build_call_expr (fldenv, 1, fenv_addr);
@@ -50960,15 +50961,17 @@ ix86_atomic_assign_expand_fenv (tree *hold, tree *clear, tree *update)
       tree stmxcsr = ix86_builtins[IX86_BUILTIN_STMXCSR];
       tree ldmxcsr = ix86_builtins[IX86_BUILTIN_LDMXCSR];
       tree stmxcsr_hold_call = build_call_expr (stmxcsr, 0);
-      tree hold_assign_orig = build2 (MODIFY_EXPR, unsigned_type_node,
-                                     mxcsr_orig_var, stmxcsr_hold_call);
+      tree hold_assign_orig = build4 (TARGET_EXPR, unsigned_type_node,
+                                     mxcsr_orig_var, stmxcsr_hold_call,
+                                     NULL_TREE, NULL_TREE);
       tree hold_mod_val = build2 (BIT_IOR_EXPR, unsigned_type_node,
                                  mxcsr_orig_var,
                                  build_int_cst (unsigned_type_node, 0x1f80));
       hold_mod_val = build2 (BIT_AND_EXPR, unsigned_type_node, hold_mod_val,
                             build_int_cst (unsigned_type_node, 0xffffffc0));
-      tree hold_assign_mod = build2 (MODIFY_EXPR, unsigned_type_node,
-                                    mxcsr_mod_var, hold_mod_val);
+      tree hold_assign_mod = build4 (TARGET_EXPR, unsigned_type_node,
+                                    mxcsr_mod_var, hold_mod_val,
+                                    NULL_TREE, NULL_TREE);
       tree ldmxcsr_hold_call = build_call_expr (ldmxcsr, 1, mxcsr_mod_var);
       tree hold_all = build2 (COMPOUND_EXPR, unsigned_type_node,
                              hold_assign_orig, hold_assign_mod);
@@ -50997,8 +51000,8 @@ ix86_atomic_assign_expand_fenv (tree *hold, tree *clear, tree *update)
                            exceptions_assign);
        }
       else
-       *update = build2 (MODIFY_EXPR, integer_type_node,
-                         exceptions_var, exceptions_sse);
+       *update = build4 (TARGET_EXPR, integer_type_node, exceptions_var,
+                         exceptions_sse, NULL_TREE, NULL_TREE);
       tree ldmxcsr_update_call = build_call_expr (ldmxcsr, 1, mxcsr_orig_var);
       *update = build2 (COMPOUND_EXPR, void_type_node, *update,
                        ldmxcsr_update_call);

diff --git a/gcc/testsuite/gcc.dg/pr94780.c b/gcc/testsuite/gcc.dg/pr94780.c
new file mode 100644 (file)
index 0000000..c4b723e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94780.c
@@ -0,0 +1,13 @@
+/* PR target/94780 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+_Atomic double x;
+
+double
+foo (void)
+{
+  double bar () { return x; }
+  x /= 3;
+  return bar ();
+}