From 4c0d1322033ce979532425d336530b217f6b5fd3 Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng@sifive.com>
Date: Fri, 3 Jul 2020 13:49:51 +0800
Subject: [PATCH] RISC-V: Disable remove unneeded save-restore call
 optimization if there are any arguments on stack.

 - This optimization will adjust stack, but it not check/update other
   stack pointer use-site, the example is when the arguments put on
   stack, the offset become wrong after optimization.

 - However adjust stack frame usage after register allocation could be
   error prone, so we decide to turn off this optimization for such case.

 - Ye-Ting Kuo report this issue on github:
   https://github.com/riscv/riscv-gcc/pull/192

gcc/ChangeLog:

	* config/riscv/riscv-sr.c (riscv_remove_unneeded_save_restore_calls):
	Abort if any arguments on stack.

gcc/testsuite/ChangeLog

	* gcc.target/riscv/save-restore-9.c: New.
---
 gcc/config/riscv/riscv-sr.c                   |  6 +++++
 .../gcc.target/riscv/save-restore-9.c         | 23 +++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/riscv/save-restore-9.c

diff --git a/gcc/config/riscv/riscv-sr.c b/gcc/config/riscv/riscv-sr.c
index 9af50ef028e..694f90c1583 100644
--- a/gcc/config/riscv/riscv-sr.c
+++ b/gcc/config/riscv/riscv-sr.c
@@ -244,6 +244,12 @@ check_for_no_return_call (rtx_insn *prologue)
 void
 riscv_remove_unneeded_save_restore_calls (void)
 {
+  /* We'll adjust stack size after this optimization, that require update every
+     sp use site, which could be unsafe, so we decide to turn off this
+     optimization if there are any arguments put on stack.  */
+  if (crtl->args.size != 0)
+    return;
+
   /* Will point to the first instruction of the function body, after the
      prologue end note.  */
   rtx_insn *body = NULL;
diff --git a/gcc/testsuite/gcc.target/riscv/save-restore-9.c b/gcc/testsuite/gcc.target/riscv/save-restore-9.c
new file mode 100644
index 00000000000..2567daeb376
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/save-restore-9.c
@@ -0,0 +1,23 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -msave-restore" } */
+
+int
+__attribute__((noinline,noclone))
+foo (int u)
+{
+  return u + 1;
+}
+
+int
+__attribute__((noinline,noclone))
+bar (int a, int b, int c, int d, int e, int f, int g, int h, int u)
+{
+  return foo (u);
+}
+
+int main()
+{
+  if (bar (1, 2, 3, 4, 5, 6, 7, 8, 9) != 10)
+    __builtin_abort();
+  return 0;
+}
-- 
2.30.2