GCC 15 SUP kernel workaround (#35)

GCC 15 fails to compile some SUP kernels. The problem seems to be
related to one of the optimization phases enabled at -O2 or above.
Workaround is to disable this specific optimization by adding the
flag -fno-tree-slp-vectorize to CKOPTFLAGS.

AMD-Internal: [CPUPL-6579]

Co-authored-by: Varaganti, Kiran <[email protected]>

Author: edwsmyth

config/haswell/make_defs.mk

@@ -66,6 +66,11 @@ endif
 # they make explicit use of the rbp register.
 CKOPTFLAGS     := $(COPTFLAGS) -O3 -fomit-frame-pointer
 ifeq ($(CC_VENDOR),gcc)
+  ifeq ($(shell test $(CC_MAJOR) -ge 15; echo $$?),0)
+    # gcc 15.1.0 fails to compile SUP kernels if -ftree-slp-vectorize
+    # is enabled, which is default in -O2 and higher
+    CKOPTFLAGS += -fno-tree-slp-vectorize
+  endif
   CKVECFLAGS     := -mavx2 -mfma -mfpmath=sse -march=haswell
   ifeq ($(GCC_OT_4_9_0),yes)
     # If gcc is older than 4.9.0, we must use a different label for -march.

config/skx/make_defs.mk

@@ -67,6 +67,11 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS) -O3 -fomit-frame-pointer
 
 ifeq ($(CC_VENDOR),gcc)
+  ifeq ($(shell test $(CC_MAJOR) -ge 15; echo $$?),0)
+    # gcc 15.1.0 fails to compile SUP kernels if -ftree-slp-vectorize
+    # is enabled, which is default in -O2 and higher
+    CKOPTFLAGS += -fno-tree-slp-vectorize
+  endif
   CKVECFLAGS     := -mavx512f -mavx512dq -mavx512bw -mavx512vl -mfpmath=sse -march=skylake-avx512
 else ifeq ($(CC_VENDOR),icc)
   CKVECFLAGS     := -xCORE-AVX512

config/zen/amd_config.cmake

@@ -58,8 +58,15 @@ endif()
 
 if(MSVC)
     set(CKVECFLAGS -mavx2 -mfma -mno-fma4 -mno-tbm -mno-xop -mno-lwp)
+
 elseif("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU")
+    if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 15.0.0)
+        # gcc 15.1.0 fails to compile SUP kernels if -ftree-slp-vectorize
+        # is enabled, which is default in -O2 and higher
+        list(APPEND CKOPTFLAGS -fno-tree-slp-vectorize)
+    endif()
     set(CKVECFLAGS -mavx2 -mfpmath=sse -mfma)
+
 elseif("${CMAKE_C_COMPILER_ID}" MATCHES "Clang")
     set(CKVECFLAGS -mavx2 -mfpmath=sse -mfma -mno-fma4 -mno-tbm -mno-xop -mno-lwp)
     execute_process(COMMAND ${CMAKE_C_COMPILER} --version OUTPUT_VARIABLE clang_full_version_string)
@@ -68,6 +75,7 @@ elseif("${CMAKE_C_COMPILER_ID}" MATCHES "Clang")
     if("${CLANG_STRING}" MATCHES "(AOCC.LLVM)")
         list(APPEND CKVECFLAGS -mllvm -disable-licm-vrp)
     endif()
+
 else()
     message(FATAL_ERROR "gcc or clang are required for this configuration.")
 endif()

config/zen/amd_config.mk

@@ -62,6 +62,11 @@ CKLPOPTFLAGS     :=
 
 ifeq ($(CC_VENDOR),gcc)
   CKVECFLAGS     := -mavx2 -mfpmath=sse -mfma
+  ifeq ($(shell test $(CC_MAJOR) -ge 15; echo $$?),0)
+    # gcc 15.1.0 fails to compile SUP kernels if -ftree-slp-vectorize
+    # is enabled, which is default in -O2 and higher
+    CKOPTFLAGS += -fno-tree-slp-vectorize
+  endif
 else ifeq ($(CC_VENDOR),clang)
   CKVECFLAGS     := -mavx2 -mfpmath=sse -mfma -mno-fma4 -mno-tbm -mno-xop -mno-lwp
   ifeq ($(strip $(shell $(CC) -v |&head -1 |grep -c 'AOCC.LLVM')),1)