Disable ThinLTO when using Clang.

Benchmarking with current Clang 12 shows that
and ThinLTO is a pessimization, see issue #3341.

closes https://github.com/official-stockfish/Stockfish/pull/3345

No functional change.

diff --git a/src/Makefile b/src/Makefile
index 55139a1f75eb92dc34e8628721cadef8f73b9b27..827ce6bb9d838930708ab6542ce04b89c411e014 100644 (file)
--- a/src/Makefile
+++ b/src/Makefile
@@ -590,7 +590,7 @@ endif
 ifeq ($(optimize),yes)
 ifeq ($(debug), no)
        ifeq ($(comp),clang)
 ifeq ($(optimize),yes)
 ifeq ($(debug), no)
        ifeq ($(comp),clang)

-               CXXFLAGS += -flto=thin
+               CXXFLAGS += -flto

                ifneq ($(findstring MINGW,$(KERNEL)),)
                        CXXFLAGS += -fuse-ld=lld
                else ifneq ($(findstring MSYS,$(KERNEL)),)
                ifneq ($(findstring MINGW,$(KERNEL)),)
                        CXXFLAGS += -fuse-ld=lld
                else ifneq ($(findstring MSYS,$(KERNEL)),)


@@ -610,7 +610,7 @@ ifeq ($(debug), no)
                        LDFLAGS += -save-temps
                endif
        else
                        LDFLAGS += -save-temps
                endif
        else

-               CXXFLAGS += -flto=thin
+               CXXFLAGS += -flto

                LDFLAGS += $(CXXFLAGS)
        endif
 
                LDFLAGS += $(CXXFLAGS)
        endif