From: Eric Botcazou <ebotcazou@multimania.com>
Date: Thu, 21 Mar 2002 09:39:18 +0000 (+0000)
Subject: re PR c/5354 (function call with two statement expressions yields incorrect result)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=312687cfa88b0e5ee2600e0349bf285b826521b9;p=gcc.git

re PR c/5354 (function call with two statement expressions yields incorrect result)

        PR c/5354
        * c-common.c (c_expand_expr): Preserve result of a statement
        expression if needed.

Co-Authored-By: Richard Henderson <rth@redhat.com>

From-SVN: r51121
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0a06dbd1b20..56349e57fad 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2002-03-21  Eric Botcazou <ebotcazou@multimania.com>
+	    Richard Henderson  <rth@redhat.com>
+
+	PR c/5354
+	* c-common.c (c_expand_expr): Preserve result of a statement
+	expression if needed.
+
 2002-03-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR bootstrap/4195
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 91f2a20476b..28920599dea 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -3574,6 +3574,7 @@ c_expand_expr (exp, target, tmode, modifier)
       {
 	tree rtl_expr;
 	rtx result;
+	bool preserve_result = false;
 
 	/* Since expand_expr_stmt calls free_temp_slots after every
 	   expression statement, we must call push_temp_slots here.
@@ -3600,12 +3601,24 @@ c_expand_expr (exp, target, tmode, modifier)
 
 	    if (TREE_CODE (last) == SCOPE_STMT
 		&& TREE_CODE (expr) == EXPR_STMT)
-	      TREE_ADDRESSABLE (expr) = 1;
+	      {
+	        TREE_ADDRESSABLE (expr) = 1;
+		preserve_result = true;
+	      }
 	  }
 
 	expand_stmt (STMT_EXPR_STMT (exp));
 	expand_end_stmt_expr (rtl_expr);
+
 	result = expand_expr (rtl_expr, target, tmode, modifier);
+	if (preserve_result && GET_CODE (result) == MEM)
+	  {
+	    if (GET_MODE (result) != BLKmode)
+	      result = copy_to_reg (result);
+	    else
+	      preserve_temp_slots (result);
+	  }
+
 	pop_temp_slots ();
 	return result;
       }
diff --git a/gcc/testsuite/gcc.c-torture/execute/20020320-1.c b/gcc/testsuite/gcc.c-torture/execute/20020320-1.c
new file mode 100644
index 00000000000..05f72c65482
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20020320-1.c
@@ -0,0 +1,23 @@
+/* PR c/5354 */
+/* Verify that GCC preserves relevant stack slots.  */
+
+extern void abort(void);
+extern void exit(int);
+
+struct large { int x, y[9]; };
+
+int main()
+{
+  int fixed;
+
+  fixed = ({ int temp1 = 2; temp1; }) - ({ int temp2 = 1; temp2; });
+  if (fixed != 1)
+    abort();
+
+  fixed = ({ struct large temp3; temp3.x = 2; temp3; }).x
+	  - ({ struct large temp4; temp4.x = 1; temp4; }).x;
+  if (fixed != 1)
+    abort();
+
+  exit(0);
+}