PR middle-end/27802

	* reg-stack.c (subst_stack_regs): Handle noreturn function calls
	that (would) return their results in stack registers.

	* gcc.dg/pr27802-1.c: New test case.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@114721 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 37 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 96ca8930f88..17355cefd1a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-06-16  Roger Sayle  <roger@eyesopen.com>
+
+	PR middle-end/27802
+	* reg-stack.c (subst_stack_regs): Handle noreturn function calls
+	that (would) return their results in stack registers.
+
 2006-06-16  Michael Matz  <matz@suse.de>
 	Richard Guenther  <rguenther@suse.de>
 
diff --git a/gcc/reg-stack.c b/gcc/reg-stack.c
index 83f4ebb081e..fc742bdce60 100644
--- a/gcc/reg-stack.c
+++ b/gcc/reg-stack.c
@@ -2282,6 +2282,16 @@ subst_stack_regs (rtx insn, stack regstack)
   if (NOTE_P (insn) || INSN_DELETED_P (insn))
     return control_flow_insn_deleted;
 
+  /* If this a noreturn call, we can't insert pop insns after it.
+     Instead, reset the stack state to empty.  */
+  if (CALL_P (insn)
+      && find_reg_note (insn, REG_NORETURN, NULL))
+    {
+      regstack->top = -1;
+      CLEAR_HARD_REG_SET (regstack->reg_set);
+      return control_flow_insn_deleted;
+    }
+
   /* If there is a REG_UNUSED note on a stack register on this insn,
      the indicated reg must be popped.  The REG_UNUSED note is removed,
      since the form of the newly emitted pop insn references the reg,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 313a39f1585..31c1fad9a38 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2006-06-16  Roger Sayle  <roger@eyesopen.com>
+
+	PR middle-end/27802
+	* gcc.dg/pr27802-1.c: New test case.
+
 2006-06-15  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/27689
diff --git a/gcc/testsuite/gcc.dg/pr27802-1.c b/gcc/testsuite/gcc.dg/pr27802-1.c
new file mode 100644
index 00000000000..839459ac01a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr27802-1.c
@@ -0,0 +1,16 @@
+/* Noreturn functions returning FP types used to confuse reg-stack on x86.  */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+double bar1() __attribute__((noreturn));
+void foo1() { bar1(); }
+
+double bar2() __attribute__((noreturn));
+double foo2() { return bar2(); }
+
+void bar3() __attribute__((noreturn));
+double foo3() { bar3(); }
+
+double bar4() __attribute__((noreturn));
+double foo4() { bar4(); }
+