[gcc r9-8887] x86: Fix up ix86_atomic_assign_expand_fenv [PR94780]

[gcc r9-8887] x86: Fix up ix86_atomic_assign_expand_fenv [PR94780]

[Jakub Jelinek]

https://gcc.gnu.org/g:1777beb6b12983b946dae4177470a319693fc0dc

commit r9-8887-g1777beb6b12983b946dae4177470a319693fc0dc
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Apr 27 21:14:52 2020 +0200

    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:
---
 gcc/config/i386/i386.c         | 23 +++++++++++++----------
 gcc/testsuite/gcc.dg/pr94780.c | 13 +++++++++++++
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index c6bc468e36b..5978e51e8ea 100644
--- 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
index 00000000000..c4b723e24b2
--- /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 ();
+}