drm/amd/display: readd -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines

arch/x86/Makefile disables SSE and SSE2 for the whole kernel.  The
AMDGPU drivers modified in this patch re-enable SSE but not SSE2.  Turn
on SSE2 to support emitting double precision floating point instructions
rather than calls to non-existent (usually available from gcc_s or
compiler_rt) floating point helper routines for Clang.

This was originally landed in:
commit 1011745073 ("drm/amd/display: add -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines")
but reverted in:
commit 193392ed9f ("Revert "drm/amd/display: add -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines"")
due to bugreports from GCC builds. Add guards to only do so for Clang.

Link: https://bugs.freedesktop.org/show_bug.cgi?id=109487
Link: https://github.com/ClangBuiltLinux/linux/issues/327

Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Nick Desaulniers 2019-07-22 15:31:05 -07:00 committed by Alex Deucher
parent 4cab85afe9
commit 0f0727d971
4 changed files with 16 additions and 0 deletions

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@ -32,6 +32,10 @@ endif
calcs_ccflags := -mhard-float -msse $(cc_stack_align)
ifdef CONFIG_CC_IS_CLANG
calcs_ccflags += -msse2
endif
CFLAGS_dcn_calcs.o := $(calcs_ccflags)
CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
CFLAGS_dcn_calc_math.o := $(calcs_ccflags) -Wno-tautological-compare

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@ -18,6 +18,10 @@ endif
CFLAGS_dcn20_resource.o := -mhard-float -msse $(cc_stack_align)
ifdef CONFIG_CC_IS_CLANG
CFLAGS_dcn20_resource.o += -msse2
endif
AMD_DAL_DCN20 = $(addprefix $(AMDDALPATH)/dc/dcn20/,$(DCN20))
AMD_DISPLAY_FILES += $(AMD_DAL_DCN20)

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@ -32,6 +32,10 @@ endif
dml_ccflags := -mhard-float -msse $(cc_stack_align)
ifdef CONFIG_CC_IS_CLANG
dml_ccflags += -msse2
endif
CFLAGS_display_mode_lib.o := $(dml_ccflags)
ifdef CONFIG_DRM_AMD_DC_DCN2_0

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@ -9,6 +9,10 @@ endif
dsc_ccflags := -mhard-float -msse $(cc_stack_align)
ifdef CONFIG_CC_IS_CLANG
dsc_ccflags += -msse2
endif
CFLAGS_rc_calc.o := $(dsc_ccflags)
CFLAGS_rc_calc_dpi.o := $(dsc_ccflags)
CFLAGS_codec_main_amd.o := $(dsc_ccflags)