[S] Change in coreboot[main]: arch/arm64: Use -mno-implicit-float with clang

[Arthur Heymans (Code Review)]

Arthur Heymans has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/81658?usp=email )

Change subject: arch/arm64: Use -mno-implicit-float with clang
......................................................................

arch/arm64: Use -mno-implicit-float with clang

This fixes building inline assembly that uses SIMD registers. This is
for instance the case in the vboot library.

Change-Id: I24fa9d9f81430ea3ecd40de4304a10c6e235fece
Signed-off-by: Arthur Heymans 
---
M toolchain.mk
1 file changed, 10 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/58/81658/1

diff --git a/toolchain.mk b/toolchain.mk
index f985e88..0292d60 100644
--- a/toolchain.mk
+++ b/toolchain.mk
@@ -60,7 +60,7 @@
 ARCHDIR-ppc64	:= ppc64

CFLAGS_arm	+=
-CFLAGS_arm64	+= -mgeneral-regs-only
+CFLAGS_arm64	+=
 CFLAGS_riscv	+=
 CFLAGS_x86_32	+=
 CFLAGS_x86_64	+= -mcmodel=large -mno-red-zone
@@ -93,6 +93,15 @@
 CFLAGS_ppc64	+= -Wstack-usage=1536
 endif

+# https://bugs.llvm.org/show_bug.cgi?id=30792
+# LLVM/clang runs into problems when encountering SIMD registers in assembly
+# with -mgeneral-regs-only. -mno-implicit-float achieves the same though.
+ifeq ($(CONFIG_COMPILER_GCC),y)
+CFLAGS_arm64	+= -mgeneral-regs-only
+else
+CFLAGS_arm64	+= -mno-implicit-float
+endif
+
 toolchain_to_dir = \
    $(foreach arch,$(ARCH_SUPPORTED),\
    $(eval CPPFLAGS_$(arch) += \