Append to lists to avoid clobbering

scripts/automator/build/clang-darwin_x86_64

@@ -1,8 +1,13 @@
 ld="ld"
 
+# OS-and-processor customizations
+cflags_release+=(-march=nehalem)
+
+# Build additions
 TYPES+=(msan usan)
 cflags_msan=("${cflags_debug[@]}" -fsanitize-recover=all -fsanitize=memory -fno-omit-frame-pointer)
 cflags_usan=("${cflags_debug[@]}" -fsanitize-recover=all -fsanitize=undefined)
 
+# Modifier additions
 MODIFIERS+=(lto)
 cflags_lto=(-flto=thin)

scripts/automator/build/clang-defaults

@@ -24,4 +24,4 @@ cflags_optinfo+=("${cflags_release[@]}" -Rpass-analysis=loop-vectorize
 
 # Modifier additions
 MODIFIERS=(fdo)
-cflags_fdo=("-fprofile-sample-use=${FDO_FILE:-${repo_root}/current.afdo}")
+cflags_fdo+=("-fprofile-sample-use=${FDO_FILE:-${repo_root}/current.afdo}")

scripts/automator/build/clang-linux_x86_64

@@ -10,4 +10,4 @@ cflags_usan=("${cflags_debug[@]}" -fsanitize-recover=all -fsanitize=undefined)
 
 # Modifier additions
 MODIFIERS+=(lto)
-cflags_lto=(-O2 -flto=thin)
+cflags_lto+=(-O2 -flto=thin)

scripts/automator/build/gcc-darwin_x86_64

@@ -16,5 +16,5 @@ cflags_tsan=("${cflags_debug[@]}" -fsanitize=thread)
 
 # Modifier additions
 MODIFIERS+=(lto)
-cflags_lto=(-flto)
-ldflags_lto=("${cflags[@]}" -flto)
+cflags_lto+=(-flto)
+ldflags_lto+=("${cflags[@]}" -flto)

scripts/automator/build/gcc-defaults

@@ -31,4 +31,5 @@ cflags_optinfo+=("${cflags_release[@]}" -fopt-info-missed
 # Modifier additions
 MODIFIERS=(fdo)
 # Override the prior optimization flag because O2 does better w/ feedback 
-cflags_fdo=("-O2 -fauto-profile=${FDO_FILE:-${repo_root}/current.afdo}")
+cflags_fdo+=("-O2 -ftree-vectorize
+              -fauto-profile=${FDO_FILE:-${repo_root}/current.afdo}")

scripts/automator/build/gcc-linux_x86_64

@@ -15,5 +15,5 @@ cflags_tsan=("${cflags_debug[@]}" -fsanitize=thread)
 
 # Modifier additions
 MODIFIERS+=(lto)
-cflags_lto=(-flto)
-ldflags_lto=("${cflags[@]}" "-flto=$(( $(nproc) + 2 ))")
+cflags_lto+=(-flto)
+ldflags_lto+=("${cflags[@]}" "-flto=$(( $(nproc) + 2 ))")

scripts/automator/build/machine-x86_64

@@ -1,3 +1,4 @@
-# Modifier additions universal for gcc and clang, but specific to x86_64:
+# Universal additions for gcc and clang, but specific to x86_64:
+
 MODIFIERS+=(native)
-cflags_native=(-march=native)
+cflags_native+=(-march=native)