From: Qing Zhao <qing.zhao@oracle.com>
Date: Thu, 10 Feb 2022 16:40:39 +0000 (+0000)
Subject: middle-end: updating the reg use in exit block for -fzero-call-used-regs [PR100775]
X-Git-Tag: basepoints/gcc-13~1130
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b32305b41dcafc5fb6974c0da3ce2f62251afdbf;p=thirdparty%2Fgcc.git

middle-end: updating the reg use in exit block for -fzero-call-used-regs [PR100775]

In the pass_zero_call_used_regs, when updating dataflow info after adding
the register zeroing sequence in the epilogue of the function, we should
call "df_update_exit_block_uses" to update the register use information in
the exit block to include all the registers that have been zeroed.

2022-02-10  Qing Zhao  <qing.zhao@oracle.com>

gcc/ChangeLog:

	PR middle-end/100775
	* function.cc (gen_call_used_regs_seq): Call
	df_update_exit_block_uses when updating df.

gcc/testsuite/ChangeLog:

	PR middle-end/100775
	* gcc.target/arm/pr100775.c: New test.
---

diff --git a/gcc/function.cc b/gcc/function.cc
index e1d2565f8d92..d5ed51a6a663 100644
--- a/gcc/function.cc
+++ b/gcc/function.cc
@@ -5941,7 +5941,7 @@ gen_call_used_regs_seq (rtx_insn *ret, unsigned int zero_regs_type)
 
       /* Update the data flow information.  */
       crtl->must_be_zero_on_return |= zeroed_hardregs;
-      df_set_bb_dirty (EXIT_BLOCK_PTR_FOR_FN (cfun));
+      df_update_exit_block_uses ();
     }
 }
 
diff --git a/gcc/testsuite/gcc.target/arm/pr100775.c b/gcc/testsuite/gcc.target/arm/pr100775.c
new file mode 100644
index 000000000000..c648cd5e8f7d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr100775.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-skip-if "" { ! { arm_thumb1_ok || arm_thumb2_ok } } } */
+/* { dg-options "-mthumb -fzero-call-used-regs=used" } */
+
+int
+foo (int x)
+{
+  return x;
+}