gentoo auto-resync : 24:03:2024 - 19:00:40

1 files changed, 11 insertions, 4 deletions

diff --git a/eclass/toolchain.eclass b/eclass/toolchain.eclass
index 03e6a5d987d1..6a515f9b5c69 100644
--- a/eclass/toolchain.eclass
+++ b/eclass/toolchain.eclass
@@ -1616,12 +1616,19 @@ gcc_do_filter_flags() {
 			[[ -z ${x} || ${x} -gt 64 ]] && break
 			l1_cache_size=$(taskset --cpu-list ${x} $(tc-getCC) -Q --help=params -O2 -march=native \
 				| awk '{ if ($1 ~ /^.*param.*l1-cache-size/) print $2; }' || die)
-			[[ -n ${l1_cache_size} && ${l1_cache_size} =~ "^[0-9]+$" ]] || break
+			[[ -n ${l1_cache_size} && ${l1_cache_size} =~ ^[0-9]+$ ]] || break
 			l1_cache_sizes[${l1_cache_size}]=1
 		done
-		# If any of them are different, just pick the first one.
-		if [[ ${#l1_cache_sizes} -gt 1 ]] ; then
-			append-flags --param=l1-cache-size=${l1_cache_size}
+		# If any of them are different, abort. We can't just pass one value of
+		# l1-cache-size because it doesn't cancel out the -march=native one.
+		if [[ ${#l1_cache_sizes[@]} -gt 1 ]] ; then
+			eerror "Different values of l1-cache-size detected!"
+			eerror "GCC will fail to bootstrap when comparing files with these flags."
+			eerror "This CPU is likely big.little/hybrid hardware with power/efficiency cores."
+			eerror "Please install app-misc/resolve-march-native and run 'resolve-march-native'"
+			eerror "to find a safe value of CFLAGS for this CPU. Note that this may vary"
+			eerror "depending on the core it ran on. taskset can be used to fix the cores used."
+			die "Varying l1-cache-size found, aborting (bug #915389, gcc PR#111768)"
 		fi
 	fi