From 5b7e6a36175c1c13803785557b17977d2a9ecd9d Mon Sep 17 00:00:00 2001
From: Ryan Moeller <ryan@iXsystems.com>
Date: Thu, 6 Feb 2020 12:24:37 -0500
Subject: [PATCH] Fix unknown cc flag -fno-ipa-sra

Clang does not recognize -fno-ipa-sra, so add a check for it.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #9946
---
 config/always-compiler-options.m4 | 21 +++++++++++++++++++++
 config/zfs-build.m4               |  5 +++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/config/always-compiler-options.m4 b/config/always-compiler-options.m4
index f903655fa..ca8b6bfcc 100644
--- a/config/always-compiler-options.m4
+++ b/config/always-compiler-options.m4
@@ -160,3 +160,24 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_OMIT_FRAME_POINTER], [
 	CFLAGS="$saved_flags"
 	AC_SUBST([NO_OMIT_FRAME_POINTER])
 ])
+
+dnl #
+dnl # Check if cc supports -fno-ipa-sra option.
+dnl #
+AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_IPA_SRA], [
+	AC_MSG_CHECKING([whether $CC supports -fno-ipa-sra])
+
+	saved_flags="$CFLAGS"
+	CFLAGS="$CFLAGS -Werror -fno-ipa-sra"
+
+	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
+		NO_IPA_SRA=-fno-ipa-sra
+		AC_MSG_RESULT([yes])
+	], [
+		NO_IPA_SRA=
+		AC_MSG_RESULT([no])
+	])
+
+	CFLAGS="$saved_flags"
+	AC_SUBST([NO_IPA_SRA])
+])
diff --git a/config/zfs-build.m4 b/config/zfs-build.m4
index 5b53e9c5c..2ee9b8eb9 100644
--- a/config/zfs-build.m4
+++ b/config/zfs-build.m4
@@ -59,9 +59,9 @@ AC_DEFUN([ZFS_AC_DEBUG], [
 ])
 
 AC_DEFUN([ZFS_AC_DEBUGINFO_ENABLE], [
-	DEBUG_CFLAGS="$DEBUG_CFLAGS -g -fno-inline -fno-ipa-sra"
+	DEBUG_CFLAGS="$DEBUG_CFLAGS -g -fno-inline $NO_IPA_SRA"
 
-	KERNEL_DEBUG_CFLAGS="$KERNEL_DEBUG_CFLAGS -fno-inline -fno-ipa-sra"
+	KERNEL_DEBUG_CFLAGS="$KERNEL_DEBUG_CFLAGS -fno-inline $NO_IPA_SRA"
 	KERNEL_MAKE="$KERNEL_MAKE CONFIG_DEBUG_INFO=y"
 
 	DEBUGINFO_ZFS="_with_debuginfo"
@@ -158,6 +158,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS], [
 	ZFS_AC_CONFIG_ALWAYS_CC_FRAME_LARGER_THAN
 	ZFS_AC_CONFIG_ALWAYS_CC_NO_FORMAT_TRUNCATION
 	ZFS_AC_CONFIG_ALWAYS_CC_NO_OMIT_FRAME_POINTER
+	ZFS_AC_CONFIG_ALWAYS_CC_NO_IPA_SRA
 	ZFS_AC_CONFIG_ALWAYS_CC_ASAN
 	ZFS_AC_CONFIG_ALWAYS_TOOLCHAIN_SIMD
 	ZFS_AC_CONFIG_ALWAYS_SYSTEM