From: qing zhao <qinzhao@gcc.gnu.org>
Date: Wed, 2 Dec 2020 22:48:02 +0000 (+0100)
Subject: rtl-optimization: Fix data flow maintenance bug in reg-stack.c [pr97777]
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2cace1cd683318e83e8a613f1aa2f2b16e37a342;p=gcc.git

rtl-optimization: Fix data flow maintenance bug in reg-stack.c [pr97777]

reg-stack pass does not maintain the data flow information correctly.
call df_insn_rescan_all after the transformation is done.

        gcc/
	PR rtl-optimization/97777
	* reg-stack.c (rest_of_handle_stack_regs): call
	df_insn_rescan_all if reg_to_stack return true.

	gcc/testsuite/
	PR rtl-optimization/97777
	* gcc.target/i386/pr97777.c: New test.
---

diff --git a/gcc/reg-stack.c b/gcc/reg-stack.c
index 8f98bd85750..3dab843f803 100644
--- a/gcc/reg-stack.c
+++ b/gcc/reg-stack.c
@@ -3426,7 +3426,8 @@ static unsigned int
 rest_of_handle_stack_regs (void)
 {
 #ifdef STACK_REGS
-  reg_to_stack ();
+  if (reg_to_stack ())
+    df_insn_rescan_all ();
   regstack_completed = 1;
 #endif
   return 0;
diff --git a/gcc/testsuite/gcc.target/i386/pr97777.c b/gcc/testsuite/gcc.target/i386/pr97777.c
new file mode 100644
index 00000000000..fcefc098637
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr97777.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O -fzero-call-used-regs=used -ffinite-math-only" } */
+
+float
+foo (void)
+{
+  return __builtin_fmod (0, 0);
+}
+