diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2c5edb5d9ed..36b080b04eb 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2007-07-06  Josh Conner  <jconner@apple.com>
+
+	PR middle-end/32602
+	PR middle-end/32603
+	* calls.c (store_one_arg): Handle arguments which are partially
+	on the stack when detecting argument overlap.
+
 2007-07-06  Bernd Schmidt  <bernd.schmidt@analog.com>
 
 	* reload1.c (choose_reload_regs): Set reload_spill_index for regs
diff --git a/gcc/calls.c b/gcc/calls.c
index aa63755d26d..e6741c83fb3 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -4326,6 +4326,7 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags,
 
 	      /* expand_call should ensure this.  */
 	      gcc_assert (!arg->locate.offset.var
+			  && arg->locate.size.var == 0
 			  && GET_CODE (size_rtx) == CONST_INT);
 
 	      if (arg->locate.offset.constant > i)
@@ -4335,7 +4336,21 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags,
 		}
 	      else if (arg->locate.offset.constant < i)
 		{
-		  if (i < arg->locate.offset.constant + INTVAL (size_rtx))
+		  /* Use arg->locate.size.constant instead of size_rtx
+		     because we only care about the part of the argument
+		     on the stack.  */
+		  if (i < (arg->locate.offset.constant
+			   + arg->locate.size.constant))
+		    sibcall_failure = 1;
+		}
+	      else
+		{
+		  /* Even though they appear to be at the same location,
+		     if part of the outgoing argument is in registers,
+		     they aren't really at the same location.  Check for
+		     this by making sure that the incoming size is the
+		     same as the outgoing size.  */
+		  if (arg->locate.size.constant != INTVAL (size_rtx))
 		    sibcall_failure = 1;
 		}
 	    }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e5486e9d177..2e0437d994b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2007-07-06  Josh Conner  <jconner@apple.com>
+
+	PR middle-end/32602
+	* gcc.dg/sibcall-8.c: New test.
+
+2007-07-06  Josh Conner  <jconner@apple.com>
+
+	PR middle-end/32603
+	* gcc.target/arm/sibcall-1.c: New test.
+
 2007-07-06  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gcc.dg/dfp/convert-dfp-round-thread.c: New test.
diff --git a/gcc/testsuite/gcc.dg/sibcall-8.c b/gcc/testsuite/gcc.dg/sibcall-8.c
new file mode 100644
index 00000000000..767040fd04b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/sibcall-8.c
@@ -0,0 +1,30 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -foptimize-sibling-calls" } */
+
+typedef struct {
+  int data[4];
+} arr16_t;
+
+int result = 0;
+
+void func2(int i, int j, arr16_t arr)
+{
+  result = (arr.data[0] != 1
+	    || arr.data[1] != 2
+	    || arr.data[2] != 3
+	    || arr.data[3] != 4);
+}
+
+void func1(int i, int j, int k, arr16_t a)
+{
+  func2(i, j, a);
+}
+
+int main(int argc, const char *argv[])
+{
+  arr16_t arr = {{1, 2, 3, 4}};
+    
+  func1(0, 0, 0, arr);
+  return result;
+}
+
diff --git a/gcc/testsuite/gcc.target/arm/sibcall-1.c b/gcc/testsuite/gcc.target/arm/sibcall-1.c
new file mode 100644
index 00000000000..77c94fdd0f8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/sibcall-1.c
@@ -0,0 +1,34 @@
+/* { dg-do compile { target { arm32 } } } */
+/* { dg-options "-O2" } */
+
+#define noinline __attribute__((noinline))
+
+typedef struct {
+  int data[4];
+} arr16_t;
+
+int result = 0;
+
+void noinline func2 (int i, int j, arr16_t arr)
+{
+  result = (arr.data[0] != 1
+	    || arr.data[1] != 2
+	    || arr.data[2] != 3
+	    || arr.data[3] != 4);
+}
+
+void func1 (int i, int j, int k, int l, int m, int n, arr16_t a)
+{
+  func2(i, j, a);
+}
+
+int main(int argc, const char *argv[])
+{
+  arr16_t arr = {{1, 2, 3, 4}};
+    
+  func1(0, 0, 0, 0, 0, 0, arr);
+  return result;
+}
+
+/* { dg-final { scan-assembler "\tb\tfunc2\n" } } */
+