From 0411ae7f08e0f5a8b02ff313d26d27a0f6d1bb34 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 15 Jan 2021 13:12:59 +0100
Subject: libatomic, libgomp, libitc: Fix bootstrap [PR70454]

The recent changes to error on mixing -march=i386 and -fcf-protection broke
bootstrap.  This patch changes lib{atomic,gomp,itm} configury, so that it
only adds -march=i486 to flags if really needed (i.e. when 486 or later isn't
on by default already).  Similarly, it will not use ifuncs if -mcx16
(or -march=i686 for 32-bit) is on by default.

2021-01-15  Jakub Jelinek  <jakub@redhat.com>

	PR target/70454
libatomic/
	* configure.tgt: For i?86 and x86_64 determine if -march=i486 needs to
	be added through preprocessor check on
	__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4.  Determine if try_ifunc is needed
	based on preprocessor check on __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16
	or __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8.
libgomp/
	* configure.tgt: For i?86 and x86_64 determine if -march=i486 needs to
	be added through preprocessor check on
	__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4.
libitm/
	* configure.tgt: For i?86 and x86_64 determine if -march=i486 needs to
	be added through preprocessor check on
	__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4.
---
 libatomic/configure.tgt | 56 ++++++++++++++++++++++++++++---------------------
 1 file changed, 32 insertions(+), 24 deletions(-)

(limited to 'libatomic')

diff --git a/libatomic/configure.tgt b/libatomic/configure.tgt
index 2f24817..670b0d7 100644
--- a/libatomic/configure.tgt
+++ b/libatomic/configure.tgt
@@ -81,32 +81,40 @@ case "${target_cpu}" in
 	ARCH=sparc
 	;;
 
-  i[3456]86)
-	case " ${CC} ${CFLAGS} " in
-	  *" -m64 "*|*" -mx32 "*)
-	    ;;
-	  *)
-	    if test -z "$with_arch"; then
-	      XCFLAGS="${XCFLAGS} -march=i486 -mtune=${target_cpu}"
-	      XCFLAGS="${XCFLAGS} -fomit-frame-pointer"
-	    fi
-	esac
-	ARCH=x86
-	# ??? Detect when -march=i686 is already enabled.
-	try_ifunc=yes
-	;;
-  x86_64)
-	case " ${CC} ${CFLAGS} " in
-	  *" -m32 "*)
+  i[3456]86 | x86_64)
+	cat > conftestx.c <<EOF
+#ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+#error need -march=i486
+#endif
+EOF
+	if ${CC} ${CFLAGS} -E conftestx.c > /dev/null 2>&1; then
+	  :
+	else
+	  if test "${target_cpu}" = x86_64; then
 	    XCFLAGS="${XCFLAGS} -march=i486 -mtune=generic"
-	    XCFLAGS="${XCFLAGS} -fomit-frame-pointer"
-	    ;;
-	  *)
-	    ;;
-	esac
+	  else
+	    XCFLAGS="${XCFLAGS} -march=i486 -mtune=${target_cpu}"
+	  fi
+	  XCFLAGS="${XCFLAGS} -fomit-frame-pointer"
+	fi
+	cat > conftestx.c <<EOF
+#ifdef __x86_64__
+#ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16
+#error need -mcx16
+#endif
+#else
+#ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
+#error need -march=i686
+#endif
+#endif
+EOF
+	if ${CC} ${CFLAGS} -E conftestx.c > /dev/null 2>&1; then
+	  try_ifunc=no
+	else
+	  try_ifunc=yes
+	fi
+	rm -f conftestx.c
 	ARCH=x86
-	# ??? Detect when -mcx16 is already enabled.
-	try_ifunc=yes
 	;;
 
   *)			ARCH="${target_cpu}" ;;
-- 
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